bluuebunny/crossref_metadata_2025 huggingface dataset:
A SIMPLE CASE OF SALT ANTAGONISM IN STARFISH EGGS
Authors: Lillie Ralph S.
Published: May 2004

The jelly surrounding the eggs of the starfish, Asterias forbesi, is insoluble in normal sea water, but rapidly swells and dissolves when the eggs are washed in a pure isotonic solution of NaCl. In the presence of a small proportion of CaCl2 this solvent and disintegrative action of the NaCl solution is entirely prevented, and in the mixed solution the jelly exhibits the same insolubility and other properties as in normal sea water.

2. This action of CaCl2 in preventing the dissolution of the jelly runs parallel with its action in preventing certain definite effects of the pure NaCl solution on the living egg (agglutination, cytolytic action, membrane formation, prevention of maturation).

3. The inference is that the essential factor in these and similar antagonistic and protective actions is the formation of solid water-insoluble colloidal salts (e.g., soaps and proteinates) of calcium (or other metal) with the structural colloids of the protoplasm. Apparently the presence of a certain proportion of such compounds is necessary to the structural stability of the living protoplasm, and especially to the water-insolubility and semipermeability of its external layer or plasma membrane. When the cell is immersed in the pure NaCl solution, water-soluble Na compounds are substituted for the insoluble Ca compounds which normally provide the necessary insolubility and coherence, and disintegration results.
DONNAN EQUILIBRIUM AND THE PHYSICAL PROPERTIES OF PROTEINS
Authors: Loeb Jacques
Published: May 2004

1. Gelatin solutions have a high viscosity which in the case of freshly prepared solutions varies under the influence of the hydrogen ion concentration in a similar way as the swelling, the osmotic pressure, and the electromotive forces. Solutions of crystalline egg albumin have under the same conditions a comparatively low viscosity which is practically independent of the pH (above 1.0). This difference in the viscosities of solutions of the two proteins seems to be connected with the fact that solutions of gelatin have a tendency to set to a Jelly while solutions of crystalline egg albumin show no such tendency at low temperature and pH above 1.0.

2. The formulæ for viscosity demand that the difference in the order of magnitude of the viscosity of the two proteins should correspond to a difference in the relative volume occupied by equal masses of the two proteins in the same volume of solution. It is generally assumed that these variations of volume of dissolved proteins are due to the hydration of the isolated protein ions, but if this view were correct the influence of pH on viscosity should be the same in the case of solutions of gelatin, of amino-acids, and of crystalline egg albumin, which, however, is not true.

3. Suspensions of powdered gelatin in water were prepared and it was found, first, that the viscosity of these suspensions is a little higher than that of gelatin solutions of the same concentration, second, that the pH influences the viscosity of these suspensions similarly as the viscosity of freshly prepared gelatin solutions, and third, that the volume occupied by the gelatin in the suspension varies similarly as the viscosity which agrees with the theories of viscosity. It is shown that this influence of the pH on the volume occupied by the gelatin granules in suspension is due to the existence of a Donnan equilibrium between the granules and the surrounding solution.
CONDUCTIVITY AND PERMEABILITY
Authors: Osterhout W. J. V.
Published: May 2004

An electrical current passing through a living plant flows partly through the cell wall and partly through the protoplasm. The relative amounts of these two portions of the current can be calculated.

The outcome of such calculations shows that the conclusions drawn from the study of the resistance of the tissue as a whole apply also to the resistance of the protoplasm, and consequently to the permeability of the protoplasm to ions.
THE STEREOTROPISM OF THE DOGFISH (MUSTELUS CALIFORNICUS) AND ITS REVERSAL THROUGH CHANGE OF INTENSITY OF THE STIMULUS
Authors: Maxwell S. S.
Published: May 2004

1. The dogfish responds to certain contact stimuli by definite stereotropic reactions. These reactions can be positive or negative.

2. The sense of the stereotropic response depends on the strength of the stimulus; a "weak" stimulus, produces a positive and a "strong" stimulus, a negative response.

3. The strength of stimulus necessary to cause a reversal of the reaction depends in part on the physiological state of the animal.

4. The stereotropic reactions occur equally well in the absence of the forebrain.
THE SELECTIVE ABSORPTION OF POTASSIUM BY ANIMAL CELLS
Authors: Mitchell Philip H. , Wilson J. Walter
Published: May 2004

1. Individual variations in the potassium content of the fresh muscles of frogs are notable even when computed as percentages of the dry solids. The potassium content averaged higher in freshly collected summer frogs than in winter frogs after a period of captivity.

2. Muscles show a loss of from 8 to 15 per cent of their potassium during perfusion with potassium-free Ringer solution but tenaciously hold the remainder.

3. Muscles, stimulated to contract under conditions that do not produce irreversible stages of fatigue, show losses of potassium no greater than those attributable to the presence of a potassium-free medium.

4. A condition favorable to the taking up of potassium probably occurs in a contracting muscle because rubidium and cesium, substances very similar to potassium in chemical and physiological behavior, are absorbed in retainable form by a contracting muscle but not by a resting one.
THE RECIPROCAL RELATION BETWEEN THE OSMOTIC PRESSURE AND THE VISCOSITY OF GELATIN SOLUTIONS
Authors: Loeb Jacques
Published: May 2004

1. These experiments confirm the conclusion that protein solutions are true solutions consisting of isolated ions and molecules, and that these solutions may or may not contain in addition solid submicroscopic particles capable of occluding water.

2. The typical influence of electrolytes on the osmotic pressure of protein solutions is due to the isolated protein ions since these alone are capable of causing a Donnan equilibrium across a membrane impermeable to the protein ions but permeable to most crystalloidal ions.

3. The similar influence of electrolytes on the viscosity of protein solutions is due to the submicroscopic solid protein particles capable of occluding water since the amount of water occluded by (or the amount of swelling of) these particles is regulated by the Donnan equilibrium.

4. These ideas are supported by the fact that the more the submicroscopic solid particles contained in a protein solution or suspension are transformed into isolated ions (e.g., by keeping gelatin solution for 1 hour or more at 45°C.) the more the viscosity of the solution is diminished while the osmotic pressure is increased, and vice versa.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Smith Edith Philip
Published: May 2004

Using these concentrations of ether (1 per cent, 3.65 per cent, 7.3 per cent), the following conclusions may be drawn.

1. The first effect of ether is to cause a depression in the rate of respiration. This is followed by a rapid rise above normal, which in turn is succeeded by a fall.

2. With all these concentrations the respiration is ultimately reduced to approximately the same level; the stronger the ether, the less time required to produce this result.

3. Even when the respiration has been reduced below normal, recovery is possible on removal from the ether, and appears to be complete, if sufficient time is allowed. If, however, the rate has been too far depressed, no recovery is possible.

4. These results extend those of Irwin on frog eggs and Fundulus embryos.
THE EFFECT OF HYDROGEN ION CONCENTRATION ON THE PRODUCTION OF CARBON DIOXIDE BY BACILLUS BUTYRICUS AND BACILLUS SUBTILIS
Authors: Brooks Matilda Moldenhauer
Published: May 2004

1. The maximum rate of CO2 production of Bacillus butyricus was found to be at a pH value of 7; of Bacillus subtilis at pH 6.8. If the pH value be raised or lowered there is a progressive decrease in the rate of production of CO2.

2. Spontaneous recovery follows the addition of alkali to either organism, while addition of acid is followed by recovery only upon addition of an equivalent amount of alkali, and is not complete except when the amount of acid is very small.
THE INACTIVATION OF TRYPSIN
Authors: Northrop John H.
Published: May 2004

1. A study has been made of the equilibrium existing between trypsin and the substances formed in the digestion of proteins which inhibit its action.

2. This substance could not be obtained by the hydrolysis of the proteins by acid or alkali. It is dialyzable.

3. The equilibrium between this substance (inhibitor) and trypsin is found to agree with the equation,

trypsin + inhibitor ⇌ trypsin-inhibitor

The equilibrium is reached instantaneously and is independent of the substrate concentration. If it be further assumed that the rate of hydrolysis is proportional to the concentration of the free trypsin and that the equilibrium conforms to the law of mass action, it is possible to calculate the experimental results by the application of the law of mass action.

4. The equilibrium has been studied by varying (a) the concentration of the inhibiting substance, (b) the concentration of trypsin, (c) the concentration of gelatin, and (d) the concentration of trypsin and inhibitor (the relative concentration of the two remaining the same). In all cases the results agree quantitatively with those predicted by the law of mass action.

5. It was found that the percentage retarding effect of the inhibiting substance on the rate of hydrolysis is independent of the hydrogen ion concentration between pH 6.3 and 10.0.

6. The fact that the experimental results agree with the mechanism outlined under 3, is contrary to the assumption that any appreciable amount of trypsin is combined with the gelatin at any one time; i.e., the velocity of the hydrolysis must depend on the time required for such a compound to form rather than for it to decompose.

7. The experiments may be considered as experimental proof of the validity of Arrhenius' explanation of Schütz's rule as applied to trypsin digestion.

8. Inactivated trypsin does not enter into the equilibrium.
THE INACTIVATION OF TRYPSIN
Authors: Northrop John H.
Published: May 2004

1. The rate of inactivation of purified trypsin solutions approximates closely that demanded by the monomolecular formula. The more carefully the solution is purified the closer the agreement with the formula.

2. The products formed by the action of trypsin on proteins renders the trypsin more stable. Gelatin and glycine have no effect.

3. The rate of inactivation of trypsin solutions containing these products does not follow the course of a monomolecular reaction but becomes progressively slower than the predicted rate.

4. The protective action of these substances is much greater if they are added all at once at the beginning of the experiment than if they are added at intervals.

These observations may be quantitatively accounted for by the hypothesis that a compound is formed between trypsin and the inhibiting substance which is stable as well as inactive, and that the rate of decomposition depends on the amount of uncombined trypsin present.

5. Trypsin is most stable at a pH of 5 and is rapidly destroyed in strongly acid or alkaline solution.

6. The protective effect of the inhibiting substances is small on the acid side of pH 5, increases from pH 5 to 7, and then remains approximately constant.
STUDIES ON BIOLUMINESCENCE
Authors: Harvey E. Newton
Published: May 2004

Among sixteen groups of luminous forms investigated by the author, in only four (fireflies, Pholas, ostracods, and Odontosyllis) is it possible to demonstrate the luciferin-luciferase reaction. In many groups this is probably due to the small amount of these substances present in the luminescent organism or to their instability. In the medusæ and pennatulids, despite a large amount of luminescent material, luciferin and luciferase cannot be demonstrated. This does not appear to be due to the presence of luciferin and luciferase in equivalent proportion, or to their instability. In fact, one is led to the conclusion that luciferin and luciferase do not exist in these forms, but such a conclusion must be regarded as merely tentative, in view of the fundamental character of the luciferin-luciferase reaction. Luciferin of one form will not luminesce with the luciferase of another form or vice versa, unless very closely related (Cypridina and Pyrocypris). All experiments emphasize the specificity of the light producing substances of Cypridina.
THE PHYSIOLOGY OF THE RESPIRATION OF FISHES IN RELATION TO THE HYDROGEN ION CONCENTRATION OF THE MEDIUM
Authors: Powers Edwin B.
Published: May 2004

1. The ability of marine fishes to absorb oxygen at low tension from the sea water is more or less dependent upon the hydrogen ion concentration of the water.

2. The ability of fishes to withstand wide variations in the range of hydrogen ion concentration of the sea water can be correlated with their habitats. The fishes that are most resistant to a wide variation in the hydrogen ion concentration are most cosmopolitan in their habitat. Those that are least resistant to a variation in the hydrogen ion concentration are the most restricted in their range of habitat.

3. There is a close correlation between the optimum condition of the sea water for the absorption of oxygen at low tension by the herring (Clupea pallasii), the condition of the sea water to which they react positive and that in which they are found most abundantly.

4. It is suggested that the variation in the ability to absorb oxygen at low tension at a given pH of individuals of a species is dependent upon the alkaline reserve of the blood of the individual fish.
THE INFLUENCE OF FEEDING THE ANTERIOR LOBE OF THE HYPOPHYSIS ON THE SIZE OF AMBYSTOMA TIGRINUM
Authors: Uhlenhuth Eduard
Published: May 2004

1. Animals of the species Ambystoma tigrinum when fed anterior lobe can reach a size far in excess of that of animals fed earthworms and presumably also of that of liver-fed animals.

2. Liver produces a rate of growth as high as that resulting from anterior lobe-feeding, but maintains growth only, until the animals reach a definite size far below that of anterior lobe-fed animals.
THE TEMPERATURE COEFFICIENT OF PHAGOCYTOSIS
Authors: Fenn Wallace O.
Published: May 2004

1. The experiments of Madsen and Watabiki on the effect of temperature on the phagocytosis of bacteria are discussed and a new analysis of their curves is given, showing that the rate of phagocytosis is very nearly a logarithmic function of the temperature from 0° to 35°C.; i.e., Q10 is constant over that range and is equal to 2.0.

2. New experiments are reported on the effect of temperature on the phagocytosis of quartz and carbon particles of uniform sizes, showing a marked increase in the temperature coefficient below 30°C.
THE PENETRATION OF CATIONS INTO LIVING CELLS
Authors: Brooks Matilda Moldenhauer
Published: May 2004

Direct tests of the cell sap of Nitella show that the protoplasm is normally permeable to Li, Cs, and Sr, and that penetration is more rapid in an unbalanced than in a balanced solution.
THE THEORETICAL RESPONSE OF LIVING CELLS TO CONTACT WITH SOLID BODIES
Authors: Fenn Wallace O.
Published: May 2004

The theoretical behavior of a hypothetical fluid cell in contact with flat and curved solid surfaces is discussed from the point of view of surface tension.

An equation is derived for calculating the equilibrium position of the cell on a flat surface in terms of the surface tensions between the cell and the plasma, the plasma and the solid surface, and the solid surface and the cell. It is shown that the same equilibrium is predicted from consideration of the contact angle between the cell and the solid body.

The relative surface energy has been calculated at various stages in the ingestion of a solid particle by a fluid cell four times as large in diameter, and it is thus shown that no particle will be ingested until the surface tensions are such that the cell would spread to infinity on a flat surface of the same substance. Here again the same equilibrium is predicted from considerations of the contact angle.

The adhesiveness of blood cells to solid substances is shown to be a pure surface tension phenomenon, but in most reactions between living cells and solid bodies the fluidity of the protoplasm is also a factor of prime importance.

The frequent occurrence of adhesiveness as a property of cells in contact with solid bodies is due in part to the fact that, by so adhering, the surface area of the cell not touching the solid is decreased.
THE MECHANISM OF GRANULAR GROWTH OF RABBIT SEPTICEMIA BACILLUS TYPE G
Authors: De Kruif Paul H.
Published: May 2004

The acid agglutination optimum of Microbes D and G is not independent of the nature of the buffer mixture. Glycocoll-HCl buffer mixtures cause complete flocculation at high CH+ (2.7 to 2.4), at which points little or no flocculation occurs with the Na lactate-lactic acid buffer series.

Beef infusion has the property of broadening the acid agglutination optimum of both Microbes D and G, bacilli of rabbit septicemia. This extension is in the direction of a lower CH+.

There is no evidence that the beef infusion has the power, per se, of agglutinating these organisms. It would seem merely to increase their sensitiveness to sedimentation in the presence of H ions.

The data presented explain the mechanism of the granular growth character of Microbe G in liquid media as compared to the diffuse growth of Microbe D.

Peptone (Fairchild), contrary to beef infusion, shifts the acid agglutination optimum of Microbes D and G in the direction of a higher CH+. Strong concentrations of peptone exhibit an inhibitory effect on the agglutination of Microbe D in the optimum zone.
THE AGGLUTINATION OF RED BLOOD CELLS IN THE PRESENCE OF BLOOD SERA
Authors: Coulter Calvin B.
Published: May 2004

1. The addition of blood serum displaces the optimum for agglutination of red blood cells in a salt-free medium to the reaction characteristic of flocculation of the serum euglobulin.

2. This effect is not due merely to a mechanical entanglement of the cells by the precipitating euglobulin, since at reactions at which the latter is soluble it protects the cells from the agglutination which occurs in its absence.

3. A combination of some sort appears therefore to take place between sheep cells and sheep, rabbit, and guinea pig serum euglobulin, and involves a condensation of the serum protein upon the surface of the red cell.

4. At the optimal point for agglutination of persensitized cells both mid- and end-piece of complement combine with the cells.

5. Agglutination is closely related to an optimal H ion concentration in the suspending fluid, and probably of the cell membrane, and not to a definite reaction in the interior of the cell.
THE INFLUENCE OF X-RAYS ON THE PROPERTIES OF BLOOD
Authors: Hussey Raymond G.
Published: May 2004

When rabbits are exposed to x-radiation as described, there results a definite change in the

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ratio of their plasma. This change is evidently one which defines a state of uncompensated alkali excess.

The time required for a maximum change in the chemical reaction is the same as that required for a maximum change in the decrease of leucocytes.

Sodium bicarbonate injected into the peritoneal cavity is followed by results identical with those observed following exposure to x-rays. The maximum changes occur in a shorter time following bicarbonate injection, but the relation between chemical and morphological changes are the same.

We consider this analogy to be an important one in that it is suggestive of a relationship between the effect of salt and the effect of x-rays.
KINETICS OF THE BIOLUMINESCENT REACTION IN CYPRIDINA. II
Authors: Amberson William R.
Published: May 2004

1. The decay curve of the light produced in the course of the luminescent reaction in Cypridina is, after the first second, in complete agreement with the theoretical expectation for a monomolecular reaction, if light intensity at any instant is assumed to be proportional to reaction velocity at that instant. It is shown that for such a reaction

log I = - kt + log Ak

and that the experimental values satisfy this equation.

2. The first second or two of the reaction is characterized by a brilliant initial flash, whose value is much too high to accord with the succeeding intensities and with the above formula. It is suggested that this initial high reaction velocity is an indication of a heterogeneous system.

3. Identical solutions run simultaneously give decay curves which check within the limits of the photographic error.

4. Stirring does not affect the reaction velocity or the form of the decay curve.

5. Reaction velocity is proportional to enzyme concentration, over the range of concentrations used in the study.

6. Changes in the concentration of the substrate do not affect the value of k, when all other factors are held constant. A diminution of luciferin concentration results only in a decrease in the value of the y-intercept, Log Ak, the two straight line plottings for two different concentrations being parallel.

7. The temperature coefficient is high, being about 4.5 for the 15–25° interval, and 3.0 for the 25–35° interval.
A NOTE ON THE ACTION OF CURARE, ATROPINE, AND NICOTINE ON THE INVERTEBRATE HEART
Authors: Carlson A. J.
Published: May 2004

1. The alkaloids (curare, atropine, and nicotine) in molluscs and arthropods stimulate and paralyze the central nervous system and peripheral (visceral) ganglia, but do not paralyze the motor nerve endings to skeletal or visceral muscle.

2. They stimulate and paralyze the denervated heart.

3. They paralyze or block the cardioinhibitory nerves, but not the cardioaccelerator nerves.

4. In the Limulus heart these drugs act primarily on the heart ganglion, not on the heart muscle or the intrinsic motor nerve fibers.
ON THE EQUILIBRIUM CONDITION BETWEEN BLOOD SERUM AND SEROUS CAVITY FLUIDS
Authors: Loeb Robert F. , Atchley Dana W. , Palmer Walter W. ,   With the Assistance of Ethel M. Benedict.
Published: May 2004

1. Comparative studies of blood serum and edema fluid from the same individual indicate that, regardless of the pathological condition present, whether the fluid be "transudate" or "exudate," certain definite qualitative chemical relations obtain.

2. The chief feature of these relations is that the edema fluid contains more Cl and less K than the blood serum; while the Na, HCO3, Ca, urea, glucose, and non-protein nitrogen exist in approximately the same concentrations in the serum and in the edema fluid. The freezing point is also the same in both fluids, while the specific conductivity is constantly higher in the edema fluid.

3. The above mentioned variations between the edema fluid and the serum appear to be related to the difference in the concentration of protein in the two solutions.

4. The relationships between blood serum and edema fluid seem to result from a simple membrane equilibrium, influenced in part by the proteins present.
THE STABILITY OF BACTERIAL SUSPENSIONS
Authors: Northrop John H. , De Kruif Paul H.
Published: May 2004

1. Measurements have been made of the potential and of the cohesive force at the surface of Bacillus typhosus and the bacillus of rabbit septicemia in solutions of various salts and acids.

2. Electrolytes in low concentration (0.01 N) affect primarily the potential, and in high concentration decrease the cohesive force.

3. As long as the cohesive force is not affected, agglutination occurs whenever the potential is reduced below about 15 millivolts.

4. When the cohesive force is decreased the critical potential is also decreased, and in concentrated salt solution no agglutination occurs even though there is no measurable potential.
THE FLOCCULATION OF BACTERIA BY PROTEINS
Authors: Eggerth Arnold H. , Bellows Margaret
Published: May 2004

1. The effect of adding pure proteins to bacterial suspensions at different H ion concentrations has been studied.

2. The zone of flocculation of protein-treated bacteria bears a significant relationship to the isoelectric point of the protein used. With the higher concentration of protein, agglutination occurs at or near the isoelectric point of that protein; at reactions acid to this, the bacteria carry a positive charge and are not agglutinated. With diminishing concentration of protein, the zone of flocculation shifts toward and goes beyond that characteristic of the untreated bacteria. This occurs both in the presence and absence of salts.

3. A diversity of other suspensions, such as sols of gold, mastic, cellulose nitrate, cellulose acetate, Fe(OH)3, oil emulsions, and erythrocytes, have been found by ourselves and others to exhibit a similar altered stability when treated with proteins in the same way.
FURTHER STUDIES ON EOSIN HEMOLYSIS
Authors: Schmidt Carl L. A. , Norman G. F.
Published: May 2004

Additional experimental work on the subject of eosin hemolysis has been carried out. This indicates that red cells may be protected against the toxic action of eosin in sunlight by the presence of inorganic reducing agents. It is pointed out that a marked parallelism exists between the substances which react with the Folin and Denis reagent and the compounds which afford protection to red cells against the photodynamic action of eosin. The property which is possessed in common by all of the substances is that they are easily oxidized, and their ability to protect red cells lies in their power of reduction. The toxic action of eosin probably involves the oxidation of tyrosine and tryptophane which are contained in the protein molecules of the stroma.
CELL PENETRATION BY ACIDS
Authors: Crozier W. J.
Published: May 2004

The penetration of acid into mantle tissue of Chromodoris zebra is accelerated after local faradic stimulation, and is retarded by brief treatment with anesthetic solutions. The spontaneous outward diffusion of intracellular pigment is an inadequate criterion of "permeability." Outward diffusion of pigment and penetration of acid are both facilitated when the tissue is artificially put under tension.
CELL PENETRATION BY ACIDS
Authors: Crozier W. J.
Published: May 2004

Measurements of the penetration of tissue from Chromodoris zebra are believed to show that a determining factor in penetration involves the establishment of a critical pH (near 3.5) in relation to superficial cell proteins. The rapidity with which this state is produced depends upon acid strength, and upon some property of the acid influencing the speed of absorption; hence it is necessary to compare acids within groups of chemical relationship.

The actual speed of penetration observed with any acid is dependent upon two influences: preliminary chemical combination with the outer protoplasm, followed by diffusion. The variation of the temperature coefficient of penetration velocity with the concentration of acid, and the effect of size (age) of individual providing the tissue sample agree in demonstrating the significant part played by diffusion. In comparing different acids, however, their mode of chemical union with the protoplasm determines the general order of penetrating ability.
CATAPHORETIC CHARGES OF COLLODION PARTICLES AND ANOMALOUS OSMOSIS THROUGH COLLODION MEMBRANES FREE FROM PROTEIN
Authors: Loeb Jacques
Published: May 2004

1. It had been shown in previous papers that when a salt solution is separated from pure water by a collodion membrane, water diffuses through the membrane as if it were positively charged and as if it were attracted by the anion of the salt in solution and repelled by the cation with a force increasing with the valency. In this paper, measurements of the P.D. across the membrane (E) are given, showing that when an electrical effect is added to the purely osmotic effect of the salt solution in the transport of water from the side of pure water to the solution, the latter possesses a considerable negative charge which increases with increasing valency of the anion of the salt and diminishes with increasing valency of the cation. It is also shown that a similar valency effect exists in the diffusion potentials between salt solutions and pure water without the interposition of a membrane.

2. This makes it probable that the driving force for the electrical transport of water from the side of pure water into solution is primarily a diffusion potential.

3. It is shown that the hydrogen ion concentration of the solution affects the transport curves and the diffusion potentials in a similar way.

4. It is shown, however, that the diffusion potential without interposition of the membrane differs in a definite sense from the P.D. across the membrane and that therefore the P.D. across the membrane (E) is a modified diffusion potential.

5. Measurements of the P.D. between collodion particles and aqueous solutions (ϵ) were made by the method of cataphoresis, which prove that water in contact with collodion particles free from protein practically always assumes a positive charge (except in the presence of salts with trivalent and probably tetravalent cations of a sufficiently high concentration).

6. It is shown that an electrical transport of water from the side of water into the solution is always superposed upon the osmotic transport when the sign of charge of the solution in the potential across the membrane (E) is opposite to that of the water in the P.D. between collodion particle and water (ϵ); supporting the theoretical deductions made by Bartell.

7. It is shown that the product of the P.D. across the membrane (E) into the cataphoretic P.D. between collodion particles and aqueous solution (ϵ) accounts in general semiquantitatively for that part of the transport of water into the solution which is due to the electrical forces responsible for anomalous osmosis.
THE STABILITY OF BACTERIAL SUSPENSIONS
Authors: De Kruif Paul H. , Northrop John H.
Published: May 2004

1. The removal of antibody from Bacillus typhosus is no more complete at pH 3 than at pH 7.

2. Approximately twelve agglutinating doses are firmly combined with the organisms. Immune body in excess of this amount is easily removable by distilled water.

3. A method of testing for the presence of immune body on the organism is described which depends on the difference in the acid agglutination of sensitized and unsensitized organisms.

4. Repeated washing in distilled water will serve to remove all the immune body from sensitized bacteria.
THE EQUIVALENCE OF AGE IN ANIMALS
Authors: Brody Samuel , Ragsdale Arthur C.
Published: May 2004

1. A method of plotting growth curves is presented which is considered more useful than the usual method in bringing out a number of important phenomena such as the equivalence of age in different animals, difference in the shape and duration of corresponding growth cycles in different animals, and also in determinating the age of maxima without resorting to complicated mathematical computations.

2. It is suggested that after the third cycle is past the conceptional age of the maximum of the third cycle may be taken as the age of reference for estimating the equivalent physiological ages in different animals. Before the age of the third cycle, the maxima of the second and first cycles are most conveniently used as points of reference.

3. It is shown that the product of the conceptional age of the maximum of the third cycle by 13, gives a value which is, with the possible exception of man, very near to the normal duration of life of animals under the most favorable conditions of life. In other words, the equivalent physiological ages in different animals bear an approximately constant linear relation to the duration of their growth periods.

4. Attention is called to certain differences in the shape and duration of the corresponding growth cycles in different animals and of the effect of sex on these cycles.
THE PERMEABILITY OF CELLS FOR OXYGEN AND ITS SIGNIFICANCE FOR THE THEORY OF STIMULATION
Authors: Harvey E. Newton
Published: May 2004

It can be demonstrated by an indicator method that living cells are as freely permeable to oxygen as dead cells, and that sudden admission of oxygen to the cell cannot account for increased oxidation as a result of stimulation. Oxygen penetrates as readily as carbon dioxide among the acids and ammonia among the alkalies.

Exposure of living plant cells to high oxygen pressures does not initiate certain oxidations (except after some hours), which proceed readily in dead plant cells in the air. In the light of the preceding statement, about the permeability of cells for oxygen, this is interpreted to mean that more oxygen enters the cell at high pressure, but that the reacting substances (chromogen and oxidase) are kept apart by some phase boundary as long as the cell is alive. Increased oxygen concentration eventually produces injury to the cell.
SOME ASPECTS OF SELECTIVE ABSORPTION
Authors: Osterhout W. J. V.
Published: May 2004

1. A mechanism exists in Valonia which prevents certain substances (Na, Mg, Ca, SO4) from reaching as high a concentration inside the cell as in the sea water which surrounds it.

2. A trapping mechanism also exists which causes K to accumulate in the cell in a concentration far in excess of that found in sea water. Practically all the K in the cell exists in the form of KCl.

3. The concentration of Cl does not differ greatly within and without.

4. These facts are not in harmony with present theories regarding the accumulation of K in living cells.
SODIUM CHLORIDE AND SELECTIVE DIFFUSION IN LIVING ORGANISMS
Authors: Loeb Jacques
Published: May 2004

1. It is shown that NaCl acts like CaCl2 or LaCl3 in preventing the diffusion of strong acids through the membrane of the egg of Fundulus with this difference only that a M/8 solution of NaCl acts like a M/1,000 solution of CaCl2 and like a M/30,000 solution of LaCl3.

2. It is shown that these salts inhibit the diffusion of non-dissociated weak acid through the membrane of the Fundulus egg but slightly if at all.

3. Both NaCl and CaCl2 accelerate the diffusion of dissociated strong alkali through the egg membrane of Fundulus and CaCl2 is more efficient in this respect than NaCl.

4. It is shown that in moderate concentrations NaCl accelerates the rate of diffusion of KCl through the membrane of the egg of Fundulus while CaCl2 does not.
THE INFLUENCE OF SALTS ON THE RATE OF DIFFUSION OF ACID THROUGH COLLODION MEMBRANES
Authors: Loeb Jacques
Published: May 2004

1. The writer had previously published the observation that if a salt solution made up in an acid solution (e.g. HCl) of a definite pH (e.g. 3.0) is separated by a collodion membrane from pure water containing the same acid of the same pH, acid is at first driven from the salt solution into the water, so that the pH of the latter becomes at first lower than that of the solution.

2. It is shown in this paper that this paradoxical phenomenon is not due to any peculiarity of the membrane but is a consequence of the well known fact that the diffusion constant of an acid is increased by a salt.
ON THE GROWTH AND RESPIRATION OF SULFUR-OXIDIZING BACTERIA
Authors: Waksman Selman A. , Starkey Robert L.
Published: May 2004

1. It is shown that Sulfomonas thiooxidans oxidizes elementary sulfur completely to sulfuric acid. Sodium thiosulfate is oxidized by this organism completely to sulfate. Sulfomonas thiooxidans differs, in this respect, from various other sulfur-oxidizing bacilli which either produce elementary sulfur, from the thiosulfate, or convert it into sulfates and persulfates.

2. The organism derives its carbon from the CO2 of the atmosphere, but is incapable of deriving the carbon from carbonates or organic matter.

3. The S:C, or ratio between the amount of sulfur oxidized to sulfate and amount of carbon assimilated chemosynthetically from the CO2 of the atmosphere, is, with elementary sulfur as a source of energy, 31.8, and with thiosulfate 64.2. The higher ratio in the case of the thiosulfate is due to the smaller amount of energy liberated in the oxidation of sulfur compound than in the elementary form.

4. Of the total energy made available in the oxidation of the sulfur to sulfuric acid, only 6.65 per cent is used by the organism for the reduction of atmospheric CO2 and assimilation of carbon.

5. Sulfates do not exert any injurious effect upon sulfur oxidation by Sulfomonas thiooxidans. Any effect obtained is due to the cation rather than the sulfate radical. Nitrates exert a distinctly injurious action both on the growth and respiration of the organism.

6. There is a definite correlation between the amount of sulfur present and velocity of oxidation, very similar to that found in the growth of yeasts and nitrifying bacteria. Oxidation reaches a maximum with about 25 gm. of sulfur added to 100 cc. of medium. However, larger amounts of sulfur have no injurious effect.

7. Dextrose does not exert any appreciable injurious effect in concentrations less than 5 per cent. The injurious effect of peptone sets in at 0.1 per cent concentration and brings sulfur oxidation almost to a standstill in 1 per cent concentration. Dextrose does not exert any appreciable influence upon sulfur oxidation and carbon assimilation from the carbon dioxide of the atmosphere.

8. Sulfomonas thiooxidans can withstand large concentrations of sulfuric acid. The oxidation of sulfur is affected only to a small extent even by 0.25 molar initial concentration of the acid. In 0.5 molar solutions, the injurious effect becomes marked. The organism may produce as much as 1.5 molar acid, without being destroyed.

9. Growth is at an optimum at a hydrogen ion concentration equivalent to pH 2.0 to 5.5, dropping down rapidly on the alkaline side, but not to such an extent on the acid, particularly when a pure culture is employed.

10. Respiration of the sulfur-oxidizing bacteria can be studied by using the filtrate of a vigorously growing culture, to which a definite amount of sulfur is added, and incubating for 12 to 24 hours.
THE PHAGOCYTOSIS OF SOLID PARTICLES
Authors: Fenn Wallace O.
Published: May 2004

1. Leucocytes ingest quartz particles more readily than carbon in acid solutions, and carbon more readily than quartz in alkaline solutions.

2. In the presence of acacia carbon is always preferred to quartz even in acid solutions.

3. Manganese dioxide particles are ingested by leucocytes with extraordinary rapidity as compared with manganese silicate or quartz.

4. Leucocytes are not attracted toward carbon or quartz particles but manganese dioxide exerts a distinct attraction for them.

5. Spores of Penicillium are ingested more readily than quartz.

6. Very small quartz particles, 1 micron in diameter, are not ingested as readily as larger particles of the same material. This result being contrary to the predictions of surface tension indicates that some other factor is involved in the ingestion of these small particles.

7. Measurements of the carbon electrode potentials and the cataphoretic charges on the particles have failed to supply an explanation for the varying relative rates of ingestion of carbon and quartz with varying hydrogen ion concentration.
A STUDY OF THE EQUILIBRIUM BETWEEN THE SO CALLED "ANTITRYPSIN" OF THE BLOOD AND TRYPSIN
Authors: Hussey Raymond G. , Northrop John H.
Published: May 2004

1. The retarding effect of plasma on the action of trypsin can be measured quantitatively.

2. The nature of the reaction involved in effecting the retardation has been subjected to an experimental study.

3. Evidence is presented which indicates that the equilibrium between the inhibitive agent and trypsin is reached practically instantaneously and is rapidly and completely reversible.

4. This equilibrium has been studied by experiments in which we have observed (1) the effect of adding increasing amounts of plasma to a constant amount of trypsin, (2) the effect of varying the amount of trypsin while the plasma was constant, (3) the effect of dilution on the trypsin-plasma mixture.

5. The results of these experiments are discussed and it is stated that they are in quantitative agreement with the law of mass action.

6. An equation was found which fits the curves for the experiments mentioned in (4). This equation was developed from the assumption that 1 molecule of trypsin combined with 1 molecule of inhibitor to form 1 molecule of trypsin-inhibitor compound. The agreement between the results calculated by this equation and the observed results is satisfactory. It is pointed out that the equation contains two arbitrary constants and the bearing this fact may have on the calculated results is discussed.

7. We conclude from the results of our study that we have adduced evidence which suggests the following statement regarding the so called "antitryptic" property of blood. The inhibitive agent and trypsin combine to form an inactive but dissociable compound. The reaction in equilibrium is expressed by the equation

Trypsin + inhibitor ⇌ trypsin-inhibitor

The conditions of equilibrium are apparently governed by the law of mass action. The behavior of the equilibrium is therefore similar to the behavior of other equilibria between different inhibitive agents and enzymes discussed in the paper.
A METHOD FOR THE QUANTITATIVE DETERMINATION OF TRYPSIN AND PEPSIN
Authors: Northrop John H. , Hussey Raymond G.
Published: May 2004

A quantitative method is described which permits a determination of the relative amount of trypsin or pepsin present in a gelatin-enzyme digestion mixture, provided the gelatin and trypsin solutions are purified.

This method is dependent upon the change in viscosity of such solutions. It is found that the time required to cause a given percentage change in the viscosity is nearly inversely proportional to the amount of enzyme present.

It is pointed out that the particular value of the method lies in the fact that enzyme reactions which take place in the presence of "buffer" salts may be studied.
THE IONIZATION OF PROTEIN CHLORIDES
Authors: Hitchcock David I.
Published: May 2004

1. By the use of the silver-silver chloride electrode, measurements have been made of the chloride ion concentrations of 1 per cent solutions of five proteins, containing from 0.001 N to 0.1 N hydrochloric acid. The hydrogen ion concentrations of the same solutions have been measured by the use of the hydrogen electrode.

2. The measurements indicate that the chlorides of gelatin, egg albumin, casein, edestin, and serum globulin are highly ionized electrolytes, ionizing to yield chloride ion and a positive protein-hydrogen ion. Their ionization is therefore similar to that of ammonium chloride.

3. The results do not support the idea that a protein chloride does not yield chloride ion on dissociation. They are not in agreement with the idea that the depressing effect of an excess of HCl on the viscosity and other colloidal properties of a protein chloride solution is due to a repression of the ionization of the protein chloride. The results are, however, in complete accord with the theory of colloidal behavior advocated by Loeb.
THE INFLUENCE OF ELECTROLYTES ON THE CATAPHORETIC CHARGE OF COLLOIDAL PARTICLES AND THE STABILITY OF THEIR SUSPENSIONS
Authors: Loeb Jacques
Published: May 2004

1. This paper gives measurements of the influence of various electrolytes on the cataphoretic P.D. of particles of collodion coated with gelatin, of particles of casein, and of particles of boiled egg albumin in water at different pH. The influence of the same electrolyte was about the same in all three proteins.

2. It was found that the salts can be divided into two groups according to their effect on the P.D. at the isoelectric point. The salts of the first group including salts of the type of NaCl, CaCl2, and Na2SO4 affect the P.D. of proteins at the isoelectric point but little; the second group includes salts with a trivalent or tetravalent ion such as LaCl3 or Na4Fe(CN)6. These latter salts produce a high P.D. on the isoelectric particles, LaCl3 making them positively and Na4Fe(CN)6 making them negatively charged. This difference in the action of the two groups of salts agrees with the observations on the effect of the same salts on the anomalous osmosis through collodion membranes coated with gelatin.

3. At pH 4.0 the three proteins have a positive cataphoretic charge which is increased by LaCl3 but not by NaCl or CaCl2, and which is reversed by Na4Fe(CN)6, the latter salt making the cataphoretic charge of the particles strongly negative.

4. At pH 5.8 the protein particles have a negative cataphoretic charge which is strongly increased by Na4Fe(CN)6 but practically not at all by Na2SO4 or NaCl, and which is reversed by LaCl3. the latter salt making the cataphoretic charge of the particles strongly positive.

5. The fact that electrolytes affect the cataphoretic P.D. of protein particles in the same way, no matter whether the protein is denatured egg albumin or a genuine protein like gelatin, furnishes proof that the solutions of genuine proteins such as crystalline egg albumin or gelatin are not diaphasic systems, since we shall show in a subsequent paper that proteins insoluble in water, e.g. denatured egg albumin, are precipitated when the cataphoretic P.D. falls below a certain critical value, while water-soluble proteins, e.g. genuine crystalline egg albumin or gelatin, stay in solution even if the P.D. of the particles falls below the critical P.D.
CIRCUS MOVEMENTS OF LIMULUS AND THE TROPISM THEORY
Authors: Cole William H.
Published: May 2004

1. Under laboratory conditions Limulus from 20 to 60 mm. in diameter are positively phototropic, and execute circus movements towards the normal side, when the median and the opposite lateral eyes are removed or covered.

2. The phototropism of Limulus may be modified or obliterated by (a) fright, (b) hunger, (c) stereotropism, (d) photokinesis, and (e) unknown stimuli.

3. Quantitative measurements of the paths of animals doing circus movements demonstrate that the amount of turning varies directly with the light intensity as follows: for 8,000 candle meters the degrees turned per centimeter were 6.73; for 2,000 candle meters, 5.23; and for 900 candle meters, 4.78. In other words, the diameter of the circle varies inversely with the light intensity.

4. The rate of locomotion per minute also varies directly with the light intensity, being 178 cm. for 8,000 candle meters, 167 for 2,000, and 157 for 900.

5. These reactions are satisfactorily explained by the tropism theory.
A NEW VISCOMETER
Authors: du Noüy P. Lecomte
Published: May 2004

A viscometer is described, particularly adapted to the measurement of colloidal solutions and physiological liquids (serum, blood), which, although doing away with the capillary tube (which is difficult to handle and to clean), requires less than 1 cc. of liquid.

The readings are rapid, from 30 seconds to 1 minute. The temperature is easily controlled and varied. The range is considerable and may be changed easily. The sensitivity is such that the viscosity of air can be measured to the 7th decimal, without any difficulty.

Its main advantage is that it makes possible the observation of the changes occurring in the viscosity of a liquid in function of time and temperature. It may be used as a recording viscometer by simply placing a recording photographic box before the mirror.
THE RATE OF GROWTH OF THE DAIRY COW
Authors: Brody Samuel , Ragsdale Arthur C. , Turner Charles W.
Published: May 2004

An extensive amount of data is presented on the growth in weight of the dairy cow from 2 to 17 years of age, covering practically the entire duration of life. The data show that after the age of 2 years the rate of growth declines in a non-cyclic manner. The course of decline in growth follows the course of decline of a monomolecular chemical reaction; that is, the percentage decline in growth with age is constant.
THE SELECTIVE ABSORPTION OF POTASSIUM BY ANIMAL CELLS
Authors: Stanton Ralph E.
Published: May 2004

By perfusing frogs for varying periods with potassium-free Ringer solutions having a pH ranging from 6.0 to 8.0, it has been determined that such solutions have little or no effect upon the retention of potassium by muscle cells.