bluuebunny/crossref_metadata_2025 huggingface dataset:
STUDIES ON THE PERMEABILITY OF MEMBRANES
Authors: Michaelis L. , Weech A. A.
Published: May 2004

The transfer number of Cl in a KCl solution within the pores of a dried collodion membrane is always lower than 0.5. It depends on the concentration of the solution and decreases in general with decreasing concentration. However, the transfer number for any given KCl concentration has the significance of a definite and constant figure only when an infinitely small amount of coulombs is allowed to pass through the system. For finite durations of electric transfer experiments a polarization effect will always change the original transfer number. This polarization consists in an accumulation of the salt at the one boundary and a diminution at the other boundary of the membrane. Again, as the transfer number strongly depends on concentration, this change in concentration will bring about in its turn a gradual change in the transfer number too. It is shown under what conditions the transfer numbers for the anion as obtained by electic transfer experiments are higher or lower than the ones expected without polarization effect. Thus, by changing the character and magnitude of the force driving the ions across the membranes, and according to the history of previous treatment of the membrane, the whole character of what we may call the specific permeablity for ions of the membrane may be varied without any substantial change of the membrane itself concerning its structure, its chemical composition, or its pore size.

Contemplation of the results obtained in this series of experiments in the light of the theoretical considerations just outlined has impressed us with the fallacy of speaking of the definite permeability of any type of membrane for electrolytes. The behavior of the membrane toward the passage of electrolytes depends on a variety of conditions. It may be recalled that different investigators have reported widely varying results concerning the permeability of certain physiological membranes for electrolytes. Such experiments as have been described in this paper may lead to an understanding of some of the factors responsible for such variations. We are aware that the collodion membrane in its simplicity is scarcely comparable to the extremely complicated biological membranes. Nevertheless any attempts to understand better the behavior of biological membranes may wisely begin with a study of the simplest prototypes.
THE RESPIRATORY QUOTIENT OF FROG NERVE DURING STIMULATION
Authors: Fenn Wallace O.
Published: May 2004

1. By means of a differential volumeter the increased oxygen consumption and the increased carbon dioxide output of frog nerve during and after stimulation have been observed.

2. Measurements of the R.Q. of nerve by this method are complicated by the retention of carbon dioxide. Attempts were made to avoid this (a) by studying the nerves at high CO2 tensions to make the retention small and (b) by calculating the amount of CO2 retained from the carbon dioxide dissociation curve of nerve and applying this value as a correction.

3. The results of both those methods when averaged together give an R.Q. of the excess metabolism of 1.19 and an R.Q. of the resting nerve of 0.97.

4. Observations on the time course of the gas exchange during stimulation indicate a delay in the appearance of the extra carbon dioxide output relative to the oxygen intake.

5. Very similar time curves can be calculated from the diffusion coefficients and the solubilities of the oxygen and the carbon dioxide.
DISSIMILARITY OF INNER AND OUTER PROTOPLASMIC SURFACES IN VALONIA
Authors: Osterhout W. J. V. , Damon E. B. , Jacques A. G.
Published: May 2004

The protoplasm of Valonia macrophysa forms a delicate layer, only a few microns in thickness, which contains numerous chloroplasts and nuclei. The outer surface is in contact with the cell wall, the inner with the vacuolar sap. As far as microscopic observation goes, these two surfaces seem alike; but measurements of potential difference indicate that they are decidedly different. We find that the chain

sap | protoplasm | sap

gives about 14.5 millivolts, the inner surface being positive to the outer. In order to explain this we may assume that the protoplasm consists of layers, the outer surface, X, differing from the inner surface, Y, and from the body of the protoplasm, W. We should then have the unsymmetrical chain

sap | X | W | Y | sap

which could produce an electromotive force.

If the two surfaces of such a very thin layer of protoplasm can be different, it is of fundamental significance for the theory of the nature of living matter.
THE RELATIVE PHYSIOLOGICAL EFFECTS OF ß-RAYS OF DIFFERENT VELOCITIES
Authors: Redfield Alfred C. , Bright Elizabeth M.
Published: May 2004

1. The physiological effect upon the eggs of Nereis of homogeneous groups of ß-rays of different velocities is proportional to their ability to ionize air.

2. ß-rays of low velocity produce a greater amount of physiological change than the same number of rays of high velocity.

3. These conclusions are consistent with, but do not prove, the view that the physiological effects of radiations from radium and x-rays are due to the production by them of an ionization of some substance in the egg.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Brooks Matilda Moldenhauer
Published: May 2004

1. In relatively low concentrations of NaCl, KCl, and CaCl2 the rate of respiration of Bacillus subtilis remains fairly constant for a period of several hours, while in the higher concentrations, there is a gradual decrease in the rate.

2. NaCl and KCl increase the rate of respiration of Bacillus subtilis somewhat at concentrations of 0.15 M and 0.2 M respectively; in sufficiently high concentrations they decrease the rate. CaCl2 increases the rate of respiration of Bacillus subtilis at a concentration of 0.05 M and decreases the rate at somewhat higher concentrations.

3. The effects of salts upon respiration show a well marked antagonism between NaCl and CaCl2, and between KCl and CaCl2. The antagonism between NaCl and KCl is slight and the antagonism curve shows two maxima.
ELECTRIFICATION OF WATER AND OSMOTIC PRESSURE
Authors: Loeb Jacques
Published: May 2004

1. Amphoteric electrolytes form salts with both acids and alkalies. It is shown for two amphoteric electrolytes, Al(OH)3 and gelatin, that in the presence of an acid salt water diffuses through a collodion membrane into a solution of these substances as if its particles were negatively charged, while water diffuses into solutions of these electrolytes, when they exist as monovalent or bivalent metal salts, as if the particles of water were positively charged. The turning point for the sign of the electrification of water seems to be near or to coincide with the isoelectric point of these two ampholytes which is a hydrogen ion concentration of about 2 x 10–5 N for gelatin and about 10–7 for Al(OH)3.

2. In conformity with the rules given in a preceding paper the apparently positively charged water diffuses with less rapidity through a collodion membrane into a solution of Ca and Ba gelatinate than into a solution of Li, Na, K, or NH4 gelatinate of the same concentration of gelatin and of hydrogen ions. Apparently negatively charged water diffuses also with less rapidity through a collodion membrane into a solution of gelatin sulfate than into a solution of gelatin chloride or nitrate of the same concentration of gelatin and of hydrogen ions.

3. If we define osmotic pressure as that additional pressure upon the solution required to cause as many molecules of water to diffuse from solution to the pure water as diffuse simultaneously in the opposite direction through the membrane, it follows that the osmotic pressure cannot depend only on the concentration of the solute but must depend also on the electrostatic effects of the ions present and that the influence of ions on the osmotic pressure must be the same as that on the initial velocity of diffusion. This assumption was put to a test in experiments with gelatin salts for which a collodion membrane is strictly semipermeable and the tests confirmed the expectation.
THE COMBINATION OF ENZYME AND SUBSTRATE
Authors: Northrop John H.
Published: May 2004

1. A quantitative method for the determination of pepsin is described depending on the change in conductivity of a digesting egg albumin solution.

2. The combination of pepsin with an insoluble substrate has been followed by this method.

3. The amount of pepsin removed from solution by a given weight of substrate is independent of the size of the particles of the substrate.

4. There is an optimum zone of hydrogen ion concentration for the combination of enzyme and substrate corresponding to the optimum for digestion.

5. It is suggested that the pepsin combines largely or entirely with the ionized protein.
INFLUENCE OF A SLIGHT MODIFICATION OF THE COLLODION MEMBRANE ON THE SIGN OF THE ELECTRIFICATION OF WATER
Authors: Loeb Jacques
Published: May 2004

1. It is shown that collodion membranes which have received one treatment with a 1 per cent gelatin solution show for a long time (if not permanently) afterwards a different osmotic behavior from collodion membranes not treated with gelatin. This difference shows itself only towards solutions of those electrolytes which have a tendency to induce a negative electrification of the water particles diffusing through the membrane, namely solutions of acids, acid salts, and of salts with trivalent and tetravalent cations; while the osmotic behavior of the two types of membranes towards solutions of salts and alkalies, which induce a positive electrification of the water particles diffusing through the membrane, is the same.

2. When we separate solutions of salts with trivalent cation, e.g. LaCl3 or AlCl3, from pure water by a collodion membrane treated with gelatin, water diffuses rapidly into the solution; while no water diffuses into the solution when the collodion membrane has received no gelatin treatment.

3. When we separate solutions of acid from pure water by a membrane previously treated with gelatin, negative osmosis occurs; i.e., practically no water can diffuse into the solution, while the molecules of solution and some water diffuse out. When we separate solutions of acid from pure water by collodion membranes not treated with gelatin, positive osmosis will occur; i.e., water will diffuse rapidly into the solution and the more rapidly the higher the valency of the anion.

4. These differences occur only in that range of concentrations of electrolytes inside of which the forces determining the rate of diffusion of water through the membrane are predominantly electrical; i.e., in concentrations from 0 to about M/16. For higher concentrations of the same electrolytes, where the forces determining the rate of diffusion are molecular, the osmotic behavior of the two types of membranes is essentially the same.

5. The differences in the osmotic behavior of the two types of membranes are not due to differences in the permeability of the membranes for solutes since it is shown that acids diffuse with the same rate through both kinds of membranes.

6. It is shown that the differences in the osmotic behavior of the two types of collodion membranes towards solutions of acids and of salts with trivalent cation are due to the fact that in the presence of these electrolytes water diffuses in the form of negatively charged particles through the membranes previously treated with gelatin, and in the form of positively charged particles through collodion membranes not treated with gelatin.

7. A treatment of the collodion membranes with casein, egg albumin, blood albumin, or edestin affects the behavior of the membrane towards salts with trivalent or tetravalent cations and towards acids in the same way as does a treatment with gelatin; while a treatment of the membranes with peptone prepared from egg albumin, with alanine, or with starch has no such effect.
CONCERNING THE HEREDITARY ADAPTATION OF ORGANISMS TO HIGHER TEMPERATURE
Authors: Northrop John H.
Published: May 2004

1. Imagos of Drosophila raised at temperatures of from 12–28.5°C. when placed at any temperature from 15–32.5°C. produce eggs which develop normally at these temperatures.

2. Imagos raised at temperatures of from 29–32.5° and then kept permanently within these temperatures produce eggs which do not develop.

3. Imagos raised at from 28.5–32.5°C. and then placed at temperatures of from 12–25°C. produce eggs which develop normally.

4. Imagos raised at from 28.5–32.5°C. placed at 15–25°C. for 24 hours or longer and then put back into a temperature of from 28.5–32.5°C., produce eggs which will develop at the latter temperature.

5. There is no evidence of any hereditary adaptation to higher temperatures.
STEREOTROPISM AS A FUNCTION OF NEUROMUSCULAR ORGANIZATION
Authors: Moore A. R.
Published: May 2004

From what has been said concerning the neuromuscular organization of the Asterias ray, it is possible to arrive at certain definite conclusions regarding the nature of the stereotropism of that organ. The righting movements from the start are not haphazard; i.e., they cannot be explained on any hypothesis of "trial and error." The excitation of the sensory cells of the dorsal sheath initiates dorsal flexure of the ray. This movement makes it possible for the tube feet of the tip to touch bottom and start the vigorous action which follows and completes the righting If the "feelers" by chance touch bottom they initiate the reaction de novo.

As to the remaining phases, the stereotropic reaction of the ray is referable to the high degree of surface sensitivity of the tube feet disks and the propagation of excitatory and inhibitory impulses, resulting from stimulation, along appropriate paths to the muscles of the ray. In this respect the tube feet may be regarded as playing a role similar to that of tropistic receptors in general. That is, unequal stimulation of the receptors causes a corresponding inequality of tone or of contraction in the musculature which ultimately results in an equilibrium of orientation to the factor involved.

It is evident that as a mechanism for righting stereotropism differs in one important respect from other tropisms. The latter depend for their operation upon unilateral effects in organisms which are dynamically bilaterally symmetrical. In stereotropism the sensitivity of the organism is not distributed in bilaterally symmetrical fashion. As a rule only the ventral side is stereosensitive; i.e., the sensitivity is unilaterally distributed. There is a tropistic action in such cases because of the fact that when the sensitive surface is only partially stimulated an unequal contraction of the musculature follows and this as a result brings the sensitive surface into such a position that it is all equally stimulated. Equal muscle tone follows and the organism is in equilibrium with its environment.
REGENERATION AND NEOTENY
Authors: Uhlenhuth Eduard
Published: May 2004

It is apparently quite certain that removal of parts of the body (limbs, tail) followed by regeneration of these parts (1) does not produce neoteny in the larvae of salamanders, and (2) has no influence upon metamorphosis.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Brooks Matilda Moldenhauer
Published: May 2004

1. Concentrations of MgCl2 up to 0.01 M have little effect upon the rate or respiration of Bacillus subtilis; at 0.03 M there is an increase in the rate, while in the higher concentrations there is a gradual decrease.

2. There is a well marked antagonism between MgCl2 and NaCl, and a very slight antagonism between MgCl2 and CaCl2.
THE INFLUENCE OF HYDROGEN ION CONCENTRATION ON THE INACTIVATION OF PEPSIN SOLUTIONS
Authors: Northrop John H.
Published: May 2004

1. Pepsin in solution at 38°C. is most stable at a hydrogen ion concentration of about 10–5 (pH 5.0).

2. Increasing the hydrogen ion concentration above pH 5.0 causes a slow increase in the rate of destruction of pepsin.

3. Decreasing the hydrogen ion concentration below pH 5.0 causes a very rapid increase in the rate of destruction of the enzyme.

4. Neither the purity of the enzyme solution nor the anion of the acid used has any marked effect on the rate of destruction or on the zone of hydrogen ion concentration in which the enzyme is most stable.

5. The existence of an optimum range of hydrogen ion concentration for the digestion of proteins by pepsin cannot be explained by the destruction of the enzyme by either too weak or too strong acid.
THE SIGNIFICANCE OF THE CAMBIUM IN THE STUDY OF CERTAIN PHYSIOLOGICAL PROBLEMS
Authors: Bailey I. W.
Published: May 2004

1. The adjacent, undifferentiated, uninucleated cells of the lateral meristem or cambium are of two distinct shapes and sizes: (1) small, more or less isodiametric initials which are of the same general order of magnitude as the cells of the terminal meristem and embryo; and (2) large, elongated initials which in certain cases may attain a length of more than 10,000 micra and a volume of 10,000,000 cubic micra. The large initials may be induced to divide to form small initials, and the latter to regenerate elongated cells of normal dimensions. Thus, the cambium affords an unusually favorable medium for the study of a number of fundamental physiological and cytological problems.

2. A study of the cambium reveals the fact that there is a very-much greater variability in the size of meristematic cells in plants than was suspected by Sachs or Strasburger, and that the working sphere of the nucleus is by no means so restricted as assumed by these investigators.

3. Although the larger cambial initials of Pinus strobus tend to have larger nuclei, the nucleocytoplasmic-relation varies within wide limits and the diploid number of chromosomes is constant. The conditions in the cambium do not support Winkler's view that there is a close correlation between chromosomal number (chromosomal mass) and cell size in the somatic tissue of plants, and that giant cells are hyperchromatic.

4. The process of cell plate formation in the cambium is a remarkable phenomenon, and one which is significant in discussing the relative merits of various theories concerning the dynamics of karyokinesis and cytokinesis.

5. The newly formed partition membranes in the cambial initials frequently intersect the side walls at angles of varying degrees of acuteness, which is in contradiction to Errera's (Plateau's) Law of Minimal Area.
THE NATURE OF THE GROWTH RATE
Authors: Reed H. S.
Published: May 2004

1. The growth rate of organisms may be considered as a chemical reaction which gives the mature organism as its end-product. The organism grows at a definite rate which is, at any moment, proportional to the amount of growth yet to be made.

2. Shoots of young pear trees measured at weekly intervals during the growing season showed a rate similar to that of an autocatalytic reaction.

3. Young walnut trees showed distinct cycles of growth in a single season, but the growth in each cycle proceeded at a rate corresponding to an autocatalytic reaction.

4. The growth rate follows a definite, quantitative course though judged by different criteria. Data are presented for maize in which green weight, dry weight, and height of the plant are used. Data for cattle show that either weight or height of the animal may be used as a criterion.
ON THE CAUSE OF THE INFLUENCE OF IONS ON THE RATE OF DIFFUSION OF WATER THROUGH COLLODION MEMBRANES. II
Authors: Loeb Jacques
Published: May 2004

1. It had been shown in previous publications that when pure water is separated from a solution of an electrolyte by a collodion membrane the ion with the same sign of charge as the membrane increases and the ion with the opposite sign of charge as the membrane diminishes the rate of diffusion of water into the solution; but that the relative influence of the oppositely charged ions upon the rate of diffusion of water through the membrane is not the same for different concentrations. Beginning with the lowest concentrations of electrolytes the attractive influence of that ion which has the same sign of charge as the collodion membrane upon the oppositely charged water increases more rapidly with increasing concentration of the electrolyte than the repelling effect of the ion possessing the opposite sign of charge as the membrane. When the concentration exceeds a certain critical value the repelling influence of the latter ion upon the water increases more rapidly with a further increase in the concentration of the electrolyte than the attractive influence of the ion having the same sign of charge as the membrane.

2. It is shown in this paper that the influence of the concentration of electrolytes on the rate of transport of water through collodion membranes in electrical endosmose is similar to that in the case of free osmosis.

3. On the basis of the Helmholtz theory of electrical double layers this seems to indicate that the influence of an electrolyte on the rate of diffusion of water through a collodion membrane in the case of free osmosis is due to the fact that the ion possessing the same sign of charge as the membrane increases the density of charge of the latter while the ion with the opposite sign diminishes the density of charge of the membrane. The relative influence of the oppositely charged ions on the density of charge of the membrane is not the same in all concentrations. The influence of the ion with the same sign of charge increases in the lowest concentrations more rapidly with increasing concentration than the influence of the ion with the opposite sign of charge, while for somewhat higher concentrations the reverse is true.
THE REVERSAL OF THE SIGN OF THE CHARGE OF MEMBRANES BY HYDROGEN IONS
Authors: Loeb Jacques
Published: May 2004

1. It had been shown in previous papers that when a collodion membrane has been treated with a protein the membrane assumes a positive charge when the hydrogen ion concentration of the solution with which it is in contact exceeds a certain limit. It is pointed out in this paper that by treating the collodion membrane with a protein (e.g. oxyhemoglobin) a thin film of protein adheres to the membrane and that the positive charge of the membrane must therefore be localized in this protein film.

2. It is further shown in this paper that the hydrogen ion concentration, at which the reversal in the sign of the charge of a collodion membrane treated with a protein occurs, varies in the same sense as the isoelectric point of the protein, with which the membrane has been treated, and is always slightly higher than that of the isoelectric point of the protein used.

3. The critical hydrogen ion concentration required for the reversal seems to be, therefore, that concentration where enough of the protein lining of the membrane is converted into a protein-acid salt (e.g. gelatin nitrate) capable of ionizing into a positive protein ion (e.g. gelatin) and the anion of the acid used (e.g. NO3).
ENZYME ACTION IN ECHINODONTIUM TINCTORIUM ELLIS AND EVERHART
Authors: Schmitz Henry
Published: May 2004

In Echinodontium tinctorium the presence of the following enzymes was demonstrated: esterase, maltase, lactase, sucrase, raffinase, diastase, inulase, cellulase, hemicellulase, urease, rennet, and catalase.
THE ANALYSIS OF NEUROMUSCULAR MECHANISMS IN CHITON
Authors: Crozier W. J.
Published: May 2004

1. The degree of curvature of the body and of the girdle of a Chiton is determined by the activity of antagonistic muscle groups. At a certain, early stage in the strychninization of a Chiton the reciprocal inhibition involved in the natural use of these muscle groups is reversed, such that extensor muscles, rather than, as normally, flexor muscles, contract as the result of stimulation. This condition involves a reversal, under strychnine, of the normally positive stereotropism of the foot, and of the usual response of the mollusk to an increased illumination of its ventral surface. Strychnine reversal of this character is not a matter of the relative strength of the opposed muscle groups, for the flexor muscles are the more powerful and are the ones always shortened in tetanic contraction.

2. Nicotine, in contrast to strychnine, primarily induces contraction of flexor muscles. Its effects, moreover, are in a degree selective, being notably exerted on "cerebral" nervous structures. Curare is devoid of characteristic action on the neuromuscular responses of Chiton.

3. The chemical organization of the neuromuscular organs of Chiton, as far as revealed by these tests, corresponds to a more simple condition than is inferred for gastropods. In particular, the behavior with respect to curare resembles more that of the neuromuscular apparatus of flatworms.
THE REVERSAL OF THE SIGN OF THE CHARGE OF COLLODION MEMBRANES BY TRIVALENT CATIONS
Authors: Loeb Jacques
Published: May 2004

1. Trivalent cations cause a collodion membrane covered with a protein film to be charged positively while they do not produce such an effect on collodion membranes not possessing a protein film. The same had been found for the reversal of the sign of charge of the membrane by acid.

2. This reversal in the sign of charge of the membrane by trivalent cations occurs on the alkaline side of the isoelectric point of the protein used; while the reversal by acid occurs on the acid side of the isoelectric point.

3. The reversal seems to be due to or to be accompanied in both cases by a chemical change in the protein. The chemical change which occurs when the hydrogen ions reverse the sign of charge of the protein film consists in the formation of a protein-acid salt whereby the H ion becomes part of a complex protein cation; while the chemical change which occurs when trivalent cations reverse the sign of charge of the protein film consists in the formation of an insoluble and therefore sparingly or non-ionizable metal proteinate.
IONIC RADIUS AND IONIC EFFICIENCY
Authors: Loeb Jacques
Published: May 2004

1. It has been shown in preceding papers that when we separate solutions of electrolytes from pure water by collodion membranes the ions with the same sign of charge as the membrane increase while the ions with the opposite sign of charge diminish the rate of diffusion of water from the side of pure water to the side of solution; and that the accelerating and depressing effects of these ions on the rate of diffusion of water increase with their valency.

2. It is shown in this paper that aside from the valency a second quantity of the ion plays a rôle in this effect, namely the radius, which in a monatomic ion means the distance between the central positive nucleus and the outermost ring or shell of electrons of the ion. In monatomic, monovalent anions the radius increases in the order Cl< Br< I (being largest in I), while for monatomic, monovalent cations it increases in the order Li< Na< K< Rb (being largest in Rb).

3. It is shown that the accelerating as well as the depressing effect of the anions mentioned increases directly with the order of magnitude of their radius and that the efficiency is greatest in the case of I which has the largest radius; while the accelerating as well as the depressing effect of cations increases inversely with the order of magnitude of their radius, Li with the smallest radius having the greatest efficiency.

4. This is intelligible on the assumption that the action of the ions is electrostatic in character, in the case of cations due to the electrostatic effect of the excess charge of their positive nucleus, and in the case of anions due to the excess charge of their captured electron. The electrostatic effect of the positive nucleus of a cation on the membrane (or any other body) will be the greater the smaller the ionic radius of the cation; and the electrostatic effect of an excess electron will be the greater the further its distance from its own positive nucleus.

5. It is suggested that this rule may possibly include polyatomic, monovalent ions (e.g. NO3, CNS, etc.) when we replace these polyatomic ions by monatomic models in which the radius is calculated in such a way as to give the model the same electrostatic effect which the polyatomic ion possesses.

6. These conclusions are in harmony with the fact that the efficiency of ions increases also with their valency.

7. It is suggested that these rules concerning the influence of the ionic radius can possibly be demonstrated in other phenomena, depending on the electrostatic effect of ions.
PHOTOCHEMISTRY OF VISUAL PURPLE
Authors: Hecht Selig
Published: May 2004

1. Visual purple solutions are prepared under such conditions that the bleaching reaction is irreversible.

2. A method is described for the colorimetric estimation of very small quantities of visual purple. By this means the kinetics of the bleaching reaction are investigated.

3. The results show that the course of the decomposition follows that of a monomolecular reaction, without any measurable period of induction or after effect.
ION SERIES AND THE PHYSICAL PROPERTIES OF PROTEINS. I
Authors: Loeb Jacques
Published: May 2004

1. This paper contains experiments on the influence of acids and alkalies on the osmotic pressure of solutions of crystalline egg albumin and of gelatin, and on the viscosity of solutions of gelatin.

2. It was found in all cases that there is no difference in the effects of HCl, HBr, HNO3, acetic, mono-, di-, and trichloracetic, succinic, tartaric, citric, and phosphoric acids upon these physical properties when the solutions of the protein with these different acids have the same pH and the same concentration of originally isoelectric protein.

3. It was possible to show that in all the protein-acid salts named the anion in combination with the protein is monovalent.

4. The strong dibasic acid H2SO4 forms protein-acid salts with a divalent anion SO4 and the solutions of protein sulfate have an osmotic pressure and a viscosity of only half or less than that of a protein chloride solution of the same pH and the same concentration of originally isoelectric protein. Oxalic acid behaves essentially like a weak dibasic acid though it seems that a small part of the acid combines with the protein in the form of divalent anions.

5. It was found that the osmotic pressure and viscosity of solutions of Li, Na, K, and NH4 salts of a protein are the same at the same pH and the same concentration of originally isoelectric protein.

6. Ca(OH)2 and Ba(OH)2 form salts with proteins in which the cation is divalent and the osmotic pressure and viscosity of solutions of these two metal proteinates are only one-half or less than half of that of Na proteinate of the same pH and the same concentration of originally isoelectric gelatin.

7. These results exclude the possibility of expressing the effect of different acids and alkalies on the osmotic pressure of solutions of gelatin and egg albumin and on the viscosity of solutions of gelatin in the form of ion series. The different results of former workers were probably chiefly due to the fact that the effects of acids and alkalies on these proteins were compared for the same quantity of acid and alkali instead of for the same pH.
THE MECHANISM OF COMPLEMENT ACTION
Authors: Brooks S. C.
Published: May 2004

It has been shown:

1. That complement exposed to ultra-violet light is not thereby sensitized to the action of heat (which indicates that it is not protein).

2. That inactivation of complement by ultra-violet light is accompanied by a decrease in its surface tension.

3. That photoinactivation of complement is not a result of any changes in hydrogen ion concentration since these are less than 0.05 pH.

4. That hydrogen ion concentrations high enough to transform serum proteins from the cation to the anion condition (i.e. past the isoelectric point) permanently inactivate complement.

These facts together with those given in previous papers lead to the following hypotheses.

1. That there is present in serum a hemolytic substance which is formed from a precursor (which may resemble lecithin) and is constantly being formed and simultaneously being broken down into inactive products.

2. That both precursor and lysin contain the same photosensitive molecular group.

3. That the lytic substance is dependent for its activity upon the state of the serum proteins.
RADIOACTIVITY AND PHYSIOLOGICAL ACTION OF POTASSIUM
Authors: Loeb Robert F.
Published: May 2004

1. The non-radioactive cesium ion can replace the potassium ion almost quantitatively in solutions required for the development of the egg of the sea urchin into swimming blastulæ.

2. Thorium chloride and uranium acetate cannot replace the potassium chloride in the solutions required for the development of the egg.

3. Thorium chloride and uranium acetate do not antagonize the action of the potassium contained in sea water upon the development of eggs.
PHOTOCHEMISTRY OF VISUAL PURPLE
Authors: Hecht Selig
Published: May 2004

The temperature coefficient of the bleaching of visual purple by light is 1.00 over a range of 30 degrees. This indicates that the monomolecular course of the reaction represents a real chemical process, as opposed to a possible diffusion process, and that the reaction is probably simple in nature.
THE AMPHOTERIC PROPERTIES OF SOME AMINO-ACIDS AND PEPTIDES
Authors: Eckweiler Herbert , Noyes Helen Miller , Falk K. George
Published: May 2004

The titration curves of solutions of glycine, alanine, α-ammo-butyric acid, leucine, glycyl-glycine, alanyl-glycine, alanyl-alanine, acetone, acetamide, urea, acetic acid, and aceturic acid were determined and some of the relations as dependent upon the chemical structures discussed.

The isoelectric points of some of the amphoteric electrolytes were found experimentally. The definition of isoelectric point, its theoretical significance, and method of calculation were considered in some detail.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Brooks Matilda Moldenhauer
Published: May 2004

1. Concentrations of La(NO3)3 up to 0.000025 M have little effect upon the rate of respiration of Bacillus subtilis; at 0.000006 M there is an increase in rate, while in higher concentrations there is a decrease in rate.

2. There is well marked antagonism between La(NO3)3 and NaCl, and very slight antagonism between La(NO3)3 and CaCl2.

3. It requires a very small amount of La(NO3)3 to antagonize NaCl, the proportions of the two salts at their maximum antagonism being 99.8 parts of NaCl and 0.2 parts of La(NO3)3.
THE RELATION BETWEEN THE WAVE-LENGTH OF LIGHT AND ITS EFFECT ON THE PHOTOSENSORY PROCESS
Authors: Hecht Selig
Published: May 2004

1. Following the description of a simple method of securing high intensities of monochromatic illumination, it is shown that the most effective portion of the spectrum for the stimulation of Mya is near λ = 500 µµ.

2. The quantitative data secured is interpreted in terms of certain photochemical findings, and as a result the absorption spectrum of the photosensitive substance of Mya is tentatively mapped out.
ION SERIES AND THE PHYSICAL PROPERTIES OF PROTEINS
Authors: Loeb Jacques
Published: May 2004

1. Ions with the opposite sign of charge as that of a protein ion diminish the swelling, osmotic pressure, and viscosity of the protein. Ions with the same sign of charge as the protein ion (with the exception of H and OH ions) seem to have no effect on these properties as long as the concentrations of electrolytes used are not too high.

2. The relative depressing effect of different ions on the physical properties of proteins is a function only of the valency and sign of charge of the ion, ions of the same sign of charge and the same valency having practically the same depressing effect on gelatin solutions of the same pH while the depressing effect increases rapidly with an increase in the valency of the ion.

3. The Hofmeister series of ions are the result of an error due to the failure to notice the influence of the addition of a salt upon the hydrogen ion concentration of the protein solution. As a consequence of this failure, effects caused by a variation in the hydrogen ion concentration of the solution were erroneously attributed to differences in the nature of the ions of the salts used.

4. It is not safe to draw conclusions concerning specific effects of ions on the swelling, osmotic pressure, or viscosity of gelatin when the concentration of electrolytes in the solution exceeds M/16, since at that concentration the values of these properties are near the minimum characteristic of the isoelectric point.
THE RATE OF OVULATION IN THE DOMESTIC FOWL DURING THE PULLET YEAR
Authors: Brody Samuel
Published: May 2004

The rate of ovulation of the domestic fowl may be expressed by the equation of an autocatalytic chemical reaction. This is not surprising in view of the fact that the rate of growth may also be expressed by such an equation, and that the rate of ovulation is probably an index of the growth of the eggs. This brings the phenomenon of ovulation in the hen under the general subject of growth, and substantiates the generality and the probability of the hypothesis that growth, or at any rate the limiting factor of growth, is an autocatalytic reaction.
THE PHAGOCYTOSIS OF SOLID PARTICLES
Authors: Fenn Wallace O.
Published: May 2004

1. A new quantitative method of measuring phagocytosis of solid particles is described.

2. A method of calculating the chances of collision between leucocytes and quartz particles of different sizes is developed.

3. The speed with which three suspensions of different sized quartz particles should be ingested by leucocytes is predicted from the calculated chances of collision, and the prediction is verified experimentally.

4. The formula for the chances of collision is also verified by varying the speed of rotation of the tubes in which the phagocytic mixtures are incubated.
THE PHAGOCYTOSIS OF SOLID PARTICLES
Authors: Fenn Wallace O.
Published: May 2004

1. By measurements of the diameter and velocity of leucocytes and of the particles in two carbon suspensions, the relative rates of ingestion of the two suspensions by the leucocytes are predicted and the predictions verified experimentally.

2. The results indicate that 4.7µ particles of carbon are ingested as readily as 3.2µ particles. The more rapid apparent rate of ingestion of the 4.7µ particles is due to their greater availability rather than the greater capability of the leucocytes.

3. There is almost no phagocytosis of carbon in absence of serum or in heated serum.

4. The clumping of unwashed leucocytes is accllerated by serum and by the ingestion of carbon.

5. The available evidence indicates that the phagocytosis of bacteria does not follow the law for a monomolecular reaction, possibly because of the toxic effect upon the leucocytes of bacterial extracts.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Inman O. L.
Published: May 2004

1. In highly hypertonic solutions of sea water the rate of respiration of Laminaria agardhii is rapidly reduced.

2. In highly hypotonic solutions the rate of respiration of Laminaria agardhii is reduced somewhat less rapidly than in the case of hypertonic solutions.

3. Hypertonic solutions of NaCl, CaCl2, and of mixtures of NaCl, and CaCl2 in the proportion of 50:1, all caused a decrease in the rate of respiration of wheat seedlings.
CHEMICAL AND PHYSICAL BEHAVIOR OF CASEIN SOLUTIONS
Authors: Loeb Jacques
Published: May 2004

The experiments on casein solutions therefore confirm the conclusion at which we arrived from the behavior of gelatin and crystalline egg albumin that the forces determining the combination between proteins and acids or alkalies are the same forces of primary valency which also determine the reaction between acids and alkalies with crystalloids, and that the valency and not the nature of the ion in combination with a protein determines the effect on the physical properties of the protein.
THE COLLOIDAL BEHAVIOR OF PROTEINS
Authors: Loeb Jacques
Published: May 2004

1. It is well known that neutral salts depress the osmotic pressure, swelling, and viscosity of protein-acid salts. Measurements of the P.D. between gelatin chloride solutions contained in a collodion bag and an outside aqueous solution show that the salt depresses the P.D. in the same proportion as it depresses the osmotic pressure of the gelatin chloride solution.

2. Measurements of the hydrogen ion concentration inside the gelatin chloride solution and in the outside aqueous solution show that the difference in pH of the two solutions allows us to calculate the P.D. quantitatively on the basis of the Nernst formula

See PDF for Equation

if we assume that the P.D. is due to a difference in the hydrogen ion concentration on the two sides of the membrane.

3. This difference in pH inside minus pH outside solution seems to be the consequence of the Donnan membrane equilibrium, which only supposes that one of the ions in solution cannot diffuse through the membrane. It is immaterial for this equilibrium whether the non-diffusible ion is a crystalloid or a colloid.

4. When acid is added to isoelectric gelatin the osmotic pressure rises at first with increasing hydrogen ion concentration, reaches a maximum at pH 3.5, and then falls again with further fall of the pH. It is shown that the P.D. of the gelatin chloride solution shows the same variation with the pH (except that it reaches its maximum at pH of about 3.9) and that the P.D. can be calculated from the difference of pH inside minus pH outside on the basis of Nernst's formula.

5. It was found in preceding papers that the osmotic pressure of gelatin sulfate solutions is only about one-half of that of gelatin chloride or gelatin phosphate solutions of the same pH and the same concentration of originally isoelectric gelatin; and that the osmotic pressure of gelatin oxalate solutions is almost but not quite the same as that of the gelatin chloride solutions of the same pH and concentration of originally isoelectric gelatin. It was found that the curves for the values for P.D. of these four gelatin salts are parallel to the curves of their osmotic pressure and that the values for pH inside minus pH outside multiplied by 58 give approximately the millivolts of these P.D.

In this preliminary note only the influence of the concentration of the hydrogen ions on the P.D. has been taken into consideration. In the fuller paper, which is to follow, the possible influence of the concentration of the anions on this quantity will have to be discussed.
STUDIES ON ENZYME ACTION
Authors: Falk K. George , McGuire Grace
Published: May 2004

A number of different methods of treatment of unripe and ripe bananas for the purpose of obtaining and studying sucrolytic and amylolytic enzymes are described.

No conclusive evidence of the presence of an amlyase could be obtained in any of the preparations.

The sucrase of unripe and ripe bananas was studied more extensively. With ripe bananas, both soluble and insoluble sucrase preparations were obtained. Conditions for converting the soluble into an insoluble form were found. The actions of the sucrase preparations as far as the hydrogen ion concentration for maximum action and the time-action relation are concerned are similar to the behavior of the yeast and the potato sucrase.
A THEORY OF INJURY AND RECOVERY
Authors: Osterhout W. J. V.
Published: May 2004

Tissues of Laminaria transferred from sea water to solutions of pure salts, and thence to other solutions of pure salts, or to sea water, behave in a manner which can be predicted by means of the equations previously developed.

The behavior of the tissue may be explained as due to a series of catenary reactions. It is possible that a similar explanation may be applied to other fundamental life processes.
THE RÔLE OF THE ACTIVITY COEFFICIENT OF THE HYDROGEN ION IN THE HYDROLYSIS OF GELATIN
Authors: Northrop John H.
Published: May 2004

1. The hydrolysis of gelatin at a constant hydrogen ion concentration follows the course of a monomolecular reaction for about one-third of the reaction.

2. If the hydrogen ion concentration is not kept constant the amount of hydrolysis in certain ranges of acidity is proportional to the square root of the time (Schütz's rule).

3. The velocity of hydrolysis in strongly acid solution (pH less than 2.0) is directly proportional to the hydrogen ion concentration as determined by the hydrogen electrode i.e., the "activity;" it is not proportional to the hydrogen ion concentration as determined by the conductivity ratio.

4. The addition of neutral salts increases the velocity of hydrolysis and the hydrogen ion concentration (as determined by the hydrogen electrode) to approximately the same extent.

5. The velocity in strongly alkaline solutions (pH greater than 10) is directly proportional to the hydroxyl ion concentration.

6. Between pH 2.0 and pH 10.0 the rate of hydrolysis is approximately constant and very much greater than would be calculated from the hydrogen and hydroxyl ion concentration. This may be roughly accounted for by the assumption that the uncombined gelatin hydrolyzes much more rapidly than the gelatin salt.
ENERGY AND VISION
Authors: du Noüy P. Lecomte
Published: May 2004

A method was devised for measuring the minimum visibile in different parts of the spectrum, as done by Langley in 1888.

The results are generally in good agreement with those given by this author, although not as close on both sides of the wave length 0.55 µ; this may be due partly to the use of a rock salt prism, to the fact that the minimum was determined by looking at a beam of diffused transmitted, instead of diffused reflected light, and also to the fact that Langley experimented with the sun, through the earth's atmosphere, and had to take into account the thickness of the atmosphere interposed and the brightness of the sky. Although his experiments were made with great care, the differences from one day to another are important. However, when he expresses the energy in absolute units, he always refers to the same mean amount of energy radiated by the sun on 1 sq. cm. This amount is certainly not constant, if one judges from the differences observed in two measurements of sensitivity of the eye of the same individual at different dates. On the contrary, for a given wave length, our measurements always agreed closely, as our source of radiation was very nearly constant, owing to the absence of a varying amount of water vapor interposed. This may in some way account for the discrepancies observed.
THE RATE OF GROWTH OF THE DOMESTIC FOWL
Authors: Brody Samuel
Published: May 2004

This paper points out the fact that the growth period of the domestic fowl is analogous to that of the mammal, being composed of three, or perhaps four, cycles; two of these cycles are postembryonic with maxima at about 8 and 18 weeks varying somewhat with the breed and two or at least one, are embryonic with maxima at 11 to 12 and 15 to 16 days of age. Hatching occurs during the first part of the second or third cycle resembling in this respect the guinea pig rather than the mouse. The velocity curves of each of these cycles are similar to and can be represented by the equation of an autocatalytic monomolecular reaction.
THE THERMOLABILITY OF COMPLEMENT, IN RELATION TO THE HYDROGEN ION CONCENTRATION
Authors: Coulter Calvin B.
Published: May 2004

1. The destruction which complement undergoes on being heated in dilution in distilled water is least at a reaction between pH 6.1 and 6.4. This depends upon the relative preservation of the midpiece function at this point. This reaction represents probably the isoelectric point of a compound of the euglobulin with some substance present also in serum.

2. During the process of thermoinactivation it is chiefly or entirely the ions of this euglobulin compound which react, and these combine or interact with substances contained in the pseudoglobulin and albumin fraction.

3. The behavior of the euglobulin is different in the anionic and in the cationic condition, since on the acid side of pH 6.1 to 6.4 the destruction by heat increases as rapidly with the acidity in the presence as in the absence of NaCl. On the alkaline side of this point the presence of NaCl protects complement from destruction because of the depression in the ionization of the euglobulin.