bluuebunny/crossref_metadata_2025_split huggingface dataset:
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.
MEMBRANE POTENTIALS AND CATAPHORETIC POTENTIALS OF PROTEINS
Authors: Loeb Jacques 
Published: May 2004

1. It has been shown in preceding publications that the membrane potentials of protein solutions or gels are determined by differences in the concentration of a common ion (e.g. hydrogen ion) inside a protein solution or protein gel and an outside aqueous solution free from protein, and that the membrane potentials can be calculated with a good degree of accuracy from Donnan's equation for membrane equilibria.
2. On the basis of the theory of electrical double layers developed by Helmholtz, we are forced to assume that the cataphoretic potentials of protein particles are determined by a difference in the concentration of the two oppositely charged ions of the same electrolyte in the two strata of an electrical double layer surrounding the protein particle but situated entirely in the aqueous solution.
3. The membrane potentials of proteins agree with the cataphoretic potentials in that the sign of charge of the protein is negative on the alkaline side and positive on the acid side of the isoelectric point of the protein in both membrane potentials and cataphoretic potentials. The two types of potential of proteins disagree, especially in regard to the action of salts with trivalent and tetravalent ions on the sign of charge of the protein. While low concentrations of these salts bring about a reversal of the sign of the cataphoretic potentials of protein particles (at least in the neighborhood of the isoelectric point), the same salts can bring the membrane potentials of proteins only to zero, but call bring about no or practically no reversal of the sign of charge of the protein. Where salts seem to bring about a reversal in the membrane potential of protein solutions, the reversal is probably in reality always due to a change in the pH.
4. We may state, as a result of our experiments, that the cataphoretic migration and the cataphoretic P.D. of protein particles or of suspended particles coated with a protein are the result of two groups of forces; namely, first, forces inherent in the protein particles (these forces being linked with the membrane equilibrium between protein particles and the outside aqueous solution); and second, forces inherent entirely in the aqueous solution surrounding the protein particles.
The forces inherent in the protein particles and linked with the membrane equilibrium prevail to such an extent over the forces inherent in the water, that the sense of the cataphoretic migration of protein particles is determined by the forces resulting from the membrane equilibrium.
STUDIES IN THE PHYSICAL CHEMISTRY OF THE PROTEINS
Authors: Cohn Edwin J. , Hendry Jessie L. 
Published: May 2004

1. The solubility in water of purified, uncombined casein has previously been reported to be 0.11 gm. in 1 liter at 25°C. This solubility represents the sum of the concentrations of the casein molecule and of the soluble ions into which it dissociates.
2. The solubility of casein has now been studied in systems containing the protein and varying amounts of sodium hydroxide. It was found that casein forms a well defined soluble disodium compound, and that solubility was completely determined by (a) the solubility of the casein molecule, and (b) the concentration of the disodium casein compound.
3. In our experiments each mol of sodium hydroxide combined with approximately 2,100 gm. of casein.
4. The equivalent combining weight of casein for this base is just half the minimal molecular weight as calculated from the sulfur and phosphorus content, and one-sixth the minimal molecular weight calculated from the tryptophane content of casein.
5. From the study of systems containing the protein and very small amounts of sodium hydroxide it was possible to determine the solubility of the casein molecule, and also the degree to which it dissociated as a divalent acid and combined with base.
6. Solubility in such systems increased in direct proportion to the amount of sodium hydroxide they contained.
7. The concentration of the soluble casein compound varied inversely as the square of the hydrogen ion concentration, directly as the solubility of the casein molecule, Su, and as the constants Ka1 and Ka2 defining its acid dissociation.
8. The product of the solubility of the casein molecule and its acid dissociation constants yields the solubility product constant, Su·Ka1·Ka2 = 2.2 x 10–12 gm. casein per liter at 25°C.
9. The solubility of the casein molecule has been estimated from this constant, and also from the relation between the solubility of the casein and the sodium hydroxide concentration, to be approximately 0.09 gm. per liter at 25°C.
10. The product of the acid dissociation constants, Ka1 and Ka2, must therefore be 24 x 10–12N.
11. It is believed that these constants completely characterize the solubility of casein in systems containing the protein and small amounts of sodium hydroxide.
SENSORY ADAPTATION AND THE STATIONARY STATE
Authors: Hecht Selig 
Published: May 2004

1. Experiments are described which measure the sensitivity of animals exposed to continued illumination to which they have become adapted. It is shown that the amount of outside light energy necessary to stimulate an adapted animal increases with the intensity of the adapting illumination.
2. The data are analyzed quantitatively in terms of the reversible reaction S ⇌ P + A shown previously to account for the photic sensitivity of these animals. This analysis demonstrates that, though the amount of incident energy necessary for a minimal response varies with the adapting intensity, the actual amount of photochemical decomposition required to set off the sensory mechanism is a constant quantity.
3. The ability of these animals to come into sensory equilibrium with any sustained illumination is accounted for quantitatively by the presence of a stationary state in the reversible photochemical reaction S ⇌ P + A during which the concentrations of the three components are constant.
4. It is shown that the concentrations of these substances at the stationary state are automatically controlled by the outside intensity. Therefore, given the sensory mechanism as a basis, the adaptation of the animals to light and the consequent changes in sensitivity, are determined entirely by the light to which the animals are exposed.
5. Because of the properties of the stationary state, and of the constancy of photochemical decomposition for a minimal effect, it is suggested that the sensory system is not only the traditional receptor system, but is also a protecting layer which stabilizes and buffers the relation between the nervous system and the environment.
THE PHOTOCHEMICAL BASIS OF ANIMAL HELIOTROPISM
Authors: Northrop John H. , Loeb Jacques 
Published: May 2004

1. Experiments on the heliotropic orientation of Limulus were made which confirmed Loeb's photochemical theory of animal heliotropism proposed first in 1888 and 1889 in experiments on insects, and later in experiments on other forms of animals.
2. It is shown that these animals are oriented by light in such a way that the product
I x t x cos α
is the same for the symmetrical photosensitive elements of the eyes or the skin, where I is the intensity of the light, t the duration of illumination, and α the angle of incidence of the light at the surface element of the photosensitive organ.
3. When this equation holds, the products of decomposition by light must be the same in symmetrical elements of the eyes or skin, and the influence of these products of decomposition on the tension of symmetrical muscles of the locomotor organs of the animal must be the same. As a consequence the animal must move in the path of light, either to or from the source of light.
THE STABILITY OF BACTERIAL SUSPENSIONS
Authors: Northrop John H. 
Published: May 2004

1. The concentrations of various salts required to agglutinate different concentrations for a suspension of typhoid bacilli sensitized with immune serum have been determined.
2. The electrolytes may be divided into two classes; (1) those with which the concentration required to agglutinate is independent of the concentration of the suspension; and (2) those with which the agglutinating concentration increases in proportion to the concentration of the suspension.
3. The salts comprised under (1) do not reverse the sign of the charge of the suspension.
4. The salts of Class (2) (with the exception of ZnSO4) do reverse the sign of the charge.