bluuebunny/crossref_metadata_2025 huggingface dataset:
THE ACTION OF ALKALIES ON PEPTIDES AND ON KETOPIPERAZINES
Authors: Levene P. A. , Pfaltz M. H.
Published: May 2004

1. The tripeptide glycyl-levo-alanyl-glycine in solution of either one or ten equivalents of alkali does not undergo racemization on standing.

2. The dipeptide levo-alanyl-glycine under the conditions given in (1) does not undergo racemization.

3. In ketopiperazines, levo-alanyl-glycine anhydride and in levo-prolyl-glycine anhydride under the influence of dilute alkalies, racemization takes place.

4. Racemization in the present experiments was never complete. The degree of racemization seems to depend, on the one hand, on the stability of the ketopiperazine ring; on the other, on the concentration of the alkali.

5. The significance of these observations will depend on the outcome of the work on a larger number of polypeptides and ketopiperazines. The work is now in progress in this laboratory.
PROTEIN FILMS ON COLLODION MEMBRANES
Authors: Hitchcock David I.
Published: May 2004

1. Collodion membranes of high permeability were found to adsorb weighable amounts of gelatin and egg albumin from solution at 37°C.

2. The effect of protein concentration could be expressed fairly well by a hyperbolic equation proposed by Langmuir for the adsorption of gases by a plane surface, while the usual parabolic adsorption equation of Freundlich did not fit the results.

3. In comparing this effect with solutions of varying pH, it was found there was a decided maximum of adsorption in solutions of isoelectric protein. The effects of acids and salts on the amount of gelatin adsorbed were like those observed by Loeb on the viscosity of gelatin solutions, but opposite in direction. The effects of pH on the amount of adsorbed gelatin and on the fluidity of the gelatin solutions were nearly parallel.

4. Membranes made impermeable by long drying took up very little or no gelatin from solution.

5. In the case of membranes of varying permeability the maximum amount of adherent gelatin increased with the permeability and thickness of the membranes, and appeared to be, within limits, a linear function of the relative pore surface of the membranes as calculated from Poiseuille's law.

6. The film of gelatin greatly decreased the permeability of the membranes, as measured by the flow of water through them. The relative cross-section of the pore openings, as calculated from the permeability measurements, was a linear function of the amount of adherent gelatin. These results led to the conclusion that the gelatin formed a film inside the pores.
STUDIES ON ENZYME ACTION
Authors: Falk K. George , Noyes Helen Miller , Sugiura Kanematsu
Published: May 2004

The ester-hydrolyzing or lipase actions of extracts of whole rats whose ages ranged from 3 days before birth to 3 years 15 days were tested on ten simple esters by the method described in previous papers. The results are presented in the form of curves, both as absolute actions and as relative actions on the different substrates. The "pictures" of the relative actions changed progressively with increasing age of the rat. For the embryo and the youngest rats, the curves approached those given by the Flexner-Jobling rat carcinoma and by a number of tumors of human origin, changing to a type characteristic of the adult rat, and appearing to revert again to some extent to the embryonic type for the oldest rats. The changes in the actions on individual esters and the relative changes in the actions on different esters are discussed in detail. The greatest increases in actions as the rats became older were found with methyl and ethyl butyrates; at the same time that the actions on some of the other esters were also found to change in characteristic ways. Similar experiments with the protease actions of the extracts of whole rats of different ages on three protein preparations did not give differences similar to those found for the lipase actions. The probable reasons for these observed differences in the two sets of enzyme actions are discussed.
THE INFLUENCE OF ALCOHOL UPON THE GROWTH OF SEEDLINGS
Authors: Pearl Raymond , Allen Agnes
Published: May 2004

In this paper it is shown that if the dry seeds of the cantaloupe (Cucumis melo) are soaked for 3 hours in solutions of ethyl alcohol of concentration ranging from 2 to 16 per cent by volume, and then germinated and grown in distilled water in the dark, the total growth attained is greater by amounts ranging from 9 to 35 per cent than is that made by seeds treated in every way identically except that they are initially soaked in distilled water instead of alcohol. It is shown that this result is not due simply to differences in osmotic pressure in the different alcohol solutions. It is probably due to a simple selective action of the alcohol which eliminates the constitutionally weak and defective seeds.
TIME RELATIONS OF GROWTH
Authors: Brody Samuel
Published: May 2004

This paper is the first in a series proposing to evaluate growth constants from the viewpoint of and by the methods of the physical chemist. After discussing the physicochemical conception of growth, tentative numerical values of two growth constants are given for several species of animals including man, and the methods of computation are discussed in detail.
GEOTROPISM AND MUSCLE TENSION IN HELIX
Authors: Cole William H.
Published: May 2004

1. The snail Helix aspersa Müller, is negatively geotropic during the daytime, but positive or indifferent at night.

2. The precision of geotropic orientation is a function of the gravity component acting on the body.

3. The rate of geotropic locomotion is also determined by the gravity component (sine of the angle of inclination).

4. The rate of upward movement is increased 1.51 times at 45° inclination by loading the snail with one-half its weight. No such increase is seen in loaded snails creeping on a horizontal surface.

5. Moderate centrifugation results in orientation and locomotion towards the center of rotation.

6. A response analogous to the homostrophic reflex occurs when a backward pull to right or to left is exerted on the shell. Bilaterally equal tension applied to the shell causes locomotion along a path parallel and opposite to the direction of the pull.

7. All the observations go to show that the stimulus for geotropic orientation and locomotion is tension of the body muscles produced by the downward pull of gravity, and that the stimulus is received by the proprioreceptors of these muscles. Otolith apparatus and analogous organs, when present, may assist in the response, but they do not seem to be requisite in all cases. Since the precision of orientation and the rate of locomotion are functions of the gravity component acting on the body, the muscle tension theory of the geotropic reactions accords fully with Loeb's tropism doctrine for animals.
FERMENTWIRKUNG UND IONENANTAGONISMUS
Authors: Höber Von Rudolf , Schürmeyer Albert
Published: May 2004

1. Invertase ist salzempfindlich nur in Gegenwart von Kolloiden, wie Gelatine, Albumin, Globulin, Lecithin; ihre Aktivität wird dabei durch die Salze herabgesetzt.

2. An den Komplexen Invertase-Globulin und Invertase-Lecithin lässt sich eine Ionenaequilibrierung von der Art des physiologischen Kationenantagonismus nachweisen; Na und K einerseits, Mg, Ca, Sr, Ba, Al, La andererseits hemmen in gewissen Konzentrationsverhäitnissen einander, so dass bei Einhaltung dieser Verhältnisse die Invertase optimal wirkt.

3. Die Salzhemmung und der Kationenantagonismus fehlen auf der sauren Seite des isoelektrischen Punkts des Globulins und Lecithins.
THE EFFECT OF EXPOSURE PERIOD AND TEMPERATURE ON THE PHOTOSENSORY PROCESS IN CIONA
Authors: Hecht Selig
Published: May 2004

1. Experiments are presented which show that the latent period in the photosensory response of Ciona is inversely proportional to the duration of the exposure period to light. From this it is found that the velocity of the chemical reaction which determines the latent period is directly proportional to the concentration of photochemical products formed during the exposure period. This is interpreted as showing that the two processes form a coupled photochemical reaction, of which the secondary reaction proceeds only in the presence of products from the primary reaction. This coupling may be a catalysis or a direct chemical relation.

2. Further experiments show that the relation between temperature and the latent period is accurately described by the Arrhenius equation in which µ = 16,200. The precise numerical value of µ tentatively identifies the latent period process as an oxidation reaction which is catalyzed by iron.

3. The photocatalytic properties of certain iron compounds are used as a model for the coupled photochemical reaction suggested for the photosensory mechanism of Ciona and Mya.
THE PHOTOLYSIS OF THE LUMINESCENT GRANULES OF EUCHARIS MULTICORNIS
Authors: Moore A. R.
Published: May 2004

1. By means of a photographic method a study was made of the photolytic effect of light on the luminescent granules of Eucharis multicornis.

2. The photolytic reaction conforms to the Bunsen-Roscoe law.

3. The velocity of the photolytic reaction is not increased by a rise in temperature.

4. The photolytic reaction proceeds as a first order reaction.
THE SWELLING AND OSMOTIC PRESSURE OF GELATIN IN SALT SOLUTIONS
Authors: Northrop John H. , Kunitz M.
Published: May 2004

1. The swelling and the osmotic pressure of gelatin at pH 4.7 have been measured in the presence of a number of salts.

2. The effect of the salts on the swelling is closely paralleled by the effect on the osmotic pressure, and the bulk modulus of the gelatin particles calculated from these figures is constant up to an increase in volume of about 800 per cent. As soon as any of the salts increase the swelling beyond this point, the bulk. modulus decreases. This is interpreted as showing that the elastic limit has been exceeded.

3. Gelatin swollen in acid returns to its original volume after removal of the acid, while gelatin swollen in salt solution does not do so. This is the expected result if, as stated above, the elastic limit had been exceeded in the salt solution.

4. The modulus of elasticity of gelatin swollen in salt solutions varies in the same way as the bulk modulus calculated from the osmotic pressure and the swelling.

5. The increase in osmotic pressure caused by the salt is reversible on removal of the salt.

6. The observed osmotic pressure is much greater than the osmotic pressure calculated from the Donnan equilibrium except in the case of AlCl3, where the calculated and observed pressures agree quite closely.

7. The increase in swelling in salt solutions is due to an increase in osmotic pressure. This increase is probably due to a change in the osmotic pressure of the gelatin itself rather than to a difference in ion concentration.
THE ACTIVATION OF STARFISH EGGS BY ACIDS
Authors: Lillie Ralph S.
Published: May 2004

1. Exposure of unfertilized starfish eggs to dilute solutions of weak acids (fatty acids, benzoic and carbonic acids) in isotonic balanced salt solution causes complete activation with the proper durations of exposure. For each acid the rate of activation (reciprocal of optimum duration) varies with concentration and temperature; at a given temperature and within a considerable range of concentrations (e.g. 0.00075 to 0.004 M for butyric acid), this rate is approximately proportional to concentration. We may thus speak of a molecular rate of action characteristic of each acid.

2. In general the molecular rate of action increases with the dissociation constant and surface activity of the acids. In the fatty acid series (up to caproic), formic acid has the most rapid effect, acting about four times as rapidly as acetic; for the other acids the order is: acetic = propionic ≦ butyric < valeric < caproic. Carbonic acid acts qualitatively like the fatty acids, but its molecular rate of action is only about one-fourteenth that of acetic acid.

3. Hydrochloric and lactic acids are relatively ineffective as activating agents, apparently because of difficulty of penetration. Lactic acid is decidedly the more effective. The action of both acids is only slightly modified by dissolving in pure (isotonic NaCl and CaCl2) instead of in balanced salt solution.

4. The rate of action of acetic acid, in concentrations of 0.002 M to 0.004 M is increased (by 10 to 20 per cent) by adding Na-acetate (0.002 to 0.016) to the solution. The degree of acceleration is closely proportional to the estimated increase in undissociated acetic acid molecules. Activation thus appears to be an effect of the undissociated acid molecules in the external solution and not of the ions. Acetate anions and H ions acting by themselves, in concentrations much higher than those of the solutions used, have no activating effect. The indications are that the undissociated molecules penetrate rapidly, the ions slowly. Having penetrated, the molecules dissociate inside the egg, yielding the ions of the acid.

5. When the rate of activation is slow, as in 0.001 M acetic acid, the addition of Na-acetate (0,008 M to 0.016 M) has a retarding effect, referable apparently to the gradual penetration of acetate ions to the site of the activation reaction with consequent depression of dissociation.

6. An estimate of the CH of those solutions (of the different activating acids) which activate the egg at the same rate indicates that their H ion concentrations are approximately equal. On the assumptions that only the undissociated molecules penetrate readily, and that the conditions of dissociation are similar inside and outside the egg, this result indicates (especially when the differences in adsorption of the acids are considered) that the rate of activation is determined by the CH at the site of the activation reaction within the egg.
THE RELATIONS OF THE INDIVIDUAL AMPULLÆ OF THE SEMICIRCULAR CANALS TO THE INDIVIDUAL EYE MUSCLES
Authors: Maxwell S. S. , Huddleston O. L.
Published: May 2004

1. The reflex effect of direct mechanical stimulation of the exposed ampulla of the horizontal canal has been graphically recorded for each of the six extrinsic muscles of the eyeball.

2. Stimulation of a horizontal ampulla evokes a strong contraction of the homolateral rectus internus and of the contralateral rectus externus; at the same time the homolateral rectus externus and the contralateral rectus internus relax.

3. A single mechanical stimulus applied to the horizontal ampulla is sometimes followed by a nystagmus resulting from a series of rhythmic contractions of the externus and internus muscles.

4. Excitation of a horizontal ampulla gives rise to weak contractions of the superior and inferior recti and of the two oblique muscles of both eyes, simultaneously with the stronger contractions of the externus and internus respectively.

5. It is pointed out that the small simultaneous contractions of the four muscles just mentioned provide a virtual axis upon which the eyeball rotates. In other words these four act as fixation muscles.

6. It is suggested that some of the abnormal responses to horizontal rotation, seen in clinical cases, are due to the inaction of one or more of the fixation muscles.
THE EFFECT OF PURE PROTEIN SOLUTIONS AND OF BLOOD SERUM ON THE DIFFUSIBILITY OF CALCIUM
Authors: Loeb Robert F. ,   With the Assistance of Emily Nichols.
Published: May 2004

1. A comparative study has been made of the diffusibility of calcium in solutions of crystalline egg albumin, serum globulin, and human blood serum.

2. In all three of these solutions, at pH 7.4, molal Ca concentrations within the membrane are greater than the calcium concentrations in the outside solutions, quite in accordance with the Donnan theory.

3. At pH 7.4, the ratio of

See PDF for Structure

varies directly with the protein concentration whether the solution be one of egg albumin, serum globulin, or blood serum. This is also in accordance with the Donnan theory.

4. On the acid side of the isoelectric point of the proteins, the concentration of Ca outside becomes greater than the concentration in the solution of blood serum or pure protein, as is demanded by the Donnan theory.

5. The magnitude of the Ca ratios on the alkaline and acid sides of the isoelectric points is probably the resultant of the Donnan equilibrium and the formation of complex Ca-protein ions. Northrop and Kunitz have shown the probability of the existence of such ions in the case of Zn++, K+, and Li+, where satisfactory electrodes have been developed for E.M.F. measurements.
ON THE RESPECTIVE PARTS PLAYED BY NEURAL AND HUMORAL INFLUENCES IN ANIMAL REACTIONS
Authors: Sharpey-Schafer E.
Published: May 2004

1. In the higher animals control of the functions of the body is dual, being partly neural and partly humoral.

2. When the control of any function is single and not dual, it is entirely neural. Exceptions to this statement appear to occur in connexion with the secretion of urine and milk, since these functions have not hitherto been shown to be under direct neural control. The mamma, and perhaps the kidney also, is, however, influenced by certain internal secretions which are themselves subJect both to neural and to humoral control.

3. The functions which are controlled both neurally and humorally are initiated by direct nervous influence: the humoral influence succeeds this.

4. In the lowest organisms possessed of a nervous system there is no evidence of humoral control, and no probability that this could be exercised, since there is no circulatory fluid, and the fluid which bathes the tissue has a composition appreciably the same as that of the environment.

5. It is, therefore, inferred that in all cases in which a dual control exists the neural, which is more rapid in its action, is primary, and the humoral secondary; and that the object of the humoral influence is to continue and prolong the effect of the neural influence, and thus to effect an economy of nervous energy.
STUDIES OF GAS AND ELECTROLYTE EQUILIBRIA IN THE BLOOD
Authors: Hastings A. Baird , Salvesen Harald A. , Sendroy Julius , Van Slyke Donald D.
Published: May 2004

1. Analyses have been made of the electrolytes and proteins of serum and transudates from human subjects.

2. The distribution ratios of HCO3, Cl, Na, and H+ deviated from unity as predicted by the Gibbs-Donnan law for similar heterogeneous systems.

3. Analyses of serum, and of artificial salt solutions approximating edema fluid in composition, after equilibration across collodion membranes showed distributions similar to those between serum and edema fluid in vivo.
TEMPERATURE AND THE MECHANISM OF LOCOMOTION IN PARAMECIUM
Authors: Glaser Otto
Published: May 2004

1. Frequency polygons in which the number of observations at each temperature is reduced to a percentage basis while the time factor is represented on a logarithmic scale, indicate that the time required by Paramecium to swim a unit distance at different temperatures varies within definite limits which are constant above 15°. Below 15° the range of variability very possibly is not the same, though probably likewise constant.

2. Logarithmic velocities deduced from mean, maximal, minimal, and modal time classes, when plotted against reciprocals of the absolute temperature, fall respectively on straight lines. These lines are parallel and give µ values of 8,000 above 15° and probably 16,000 below.

3. This implies that the mechanism of locomotion in Paramecium remains essentially unaltered by a rise in temperature from 15° to 30°, and probably remains in a similar sense constant from 6° to 15°.

4. The theoretical interpretation of this result is possible in terms of a catenary series 0 → A → E in which the passages 0 → A and A → E are controlled by two catalysts differing respectively in concentration in different individuals and perhaps at different times in the same individual, but depending for their effective concentration on reactions having temperature coefficients identical with those which at each temperature characterize the biological process under consideration.
THE EFFECT OF X-RAYS ON THE IRRITABILITY OF MUSCLES IN THE FROG
Authors: Kushner Irving
Published: May 2004

Exposure of the muscle preparation of the frog to the x-rays is accompanied by a better maintenance of muscular irritability than in the case of the non-exposed preparation. This is shown by its response to a smaller electrical stimulus than the control muscle.
A COMPARISON OF BONE GROWTH IN LENGTH WITH BONE GROWTH IN WEIGHT
Authors: Hammett Frederick S.
Published: May 2004

1. The growth capacity in length of the humerus and femur of male and female albino rats during the growth period from 23 to 150 days of age is less than the growth capacity in weight. This shows that the processes productive of bone strength are more active than those concerned in longitudinal expansion or stature.

2. Growth capacity in length is less affected than is growth capacity in weight by the systemic determinants and the factors incident to sex, weaning, and puberty. Since the findings as a whole are consistent with the assumption that bone growth in length is largely a matter of increase in cell number, while bone growth in weight is largely a matter of increase in cell size and density, the generalization is made that, in the bones at least, growth by increase in cell number is more stable than growth by increase in cell size and density.

3. A stabilization and approximation to a uniform level of growth capacity in both length and weight occurs at the culmination of puberty, which is quite like that taking place in the chemical differentiation at the same time.

4. Bone growth in length is more like body growth in length than bone growth in weight is like body growth in weight.
THE INFLUENCE OF THE INTENSITY OF LIGHT ON THE RATE OF GROWTH AND DURATION OF LIFE OF DROSOPHILA
Authors: Northrop John H.
Published: May 2004

The duration of the larval and imago periods of Drosophila cultures which had been previously grown in the dark for 200 generations has been determined at various light intensities.

1. The duration of the larval period is shortened slightly at intensities around 2,500 meter candles, but becomes increasingly longer at higher intensities. The larvæ are killed by continuous exposure to light of 7,000 to 10,000 meter candles.

2. The pupæ are killed at intensities greater than 5,000 meter candles.

3. Above 1,000 meter candles the duration of the imago period is rapidly shortened.

4. The duration of life of the imago at different intensities of illumination can be quite accurately predicted by assuming that the light produces an independent "rate of aging" which is proportional to the intensity of the light.

5. The result of short exposure of the imago shows that light does not merely accelerate the normal "rate of aging," and also that the effect is only partially reversible.

Diffuse daylight does not affect the upper temperature limit of growth.
SOME CONSEQUENCES OF THE THEORY OF MEMBRANE EQUILIBRIA
Authors: Hitchcock David I.
Published: May 2004

In applying Donnan's theory of membrane equilibria to systems where the non-diffusible ion is furnished by a weak acid, base, or ampholyte, certain new relations have been derived. Equations have been deduced which give the ion ratio and the apparent osmotic pressure as functions of the concentration and ionization constant of the weak electrolyte, and of the hydrogen ion concentration in its solution. The conditions for maximum values of these two properties have been formulated. It is pointed out that the progressive addition of acid to a system containing a non-diffusible weak base should not cause the value of the membrane potential to rise, pass through a maximum, and fall, but should only cause it to diminish. It is shown that the theory predicts slight differences in the effect of salts on the ion ratio in such systems, the effect increasing with the valence of the cation.
ON SOME GENERAL PROPERTIES OF PROTEINS
Authors: Anson M. L. , Mirsky A. E.
Published: May 2004

1. The processes of denaturation and coagulation of hemoglobin are like those of other proteins.

2. When hemoglobin is denatured it is probably depolymerized into hemochromogen.

3. When other proteins are denatured they, too, are probably depolymerized. Conversely, native proteins can be regarded as aggregates of denatured proteins.

4. The globins and histones are to be regarded as denatured proteins rather than as a distinct group of proteins.

5. The factors affecting the equilibrium between native and denatured proteins have been considered.

6. A non-polar group is uncovered when a protein is denatured.

7. It has been shown that judged by the two most sensitive tests for the specificity of proteins, it is only when proteins are in the native form that they are highly specific.
A MICRO DISSECTION OF THE PACHYTENE THREADS OF TRADESCANTIA VIRGINICA L. WITH OBSERVATIONS ON SOME ASPECTS OF MITOSIS
Authors: Sands Harold C.
Published: May 2004

A micro dissection of the pachytene threads of Tradescantia virginica L. shows that the relation of the chromosomes is a matter of continuous linkage in a chain and that, undoubtedly, division and segregation are everywhere processes of abstriction with subsequent mechanical distribution of the elements.
THE CARBON DIOXIDE EXCRETED IN ONE MINUTE BY ONE CENTIMETER OF NERVE-FIBER
Authors: Parker G. H.
Published: May 2004

One centimeter of nerve-fiber from the lateral-line nerve of the dogfish is estimated to excrete on the average 4.2 x 10–8 mg. CO2 per minute.
THE EFFECT OF THE H ION CONCENTRATION ON THE AVAILABILITY OF IRON FOR CHLORELLA SP
Authors: Hopkins E. F. , Wann F. B.
Published: May 2004

The data obtained in these experiments indicate clearly that unless the necessary precautions are taken to keep the iron of the culture medium in solution the results obtained by varying the H ion concentration will not represent the true effect of this factor on growth. The availability of iron in nutrient solutions has been the subject of numerous recent investigations and it is now known that iron is precipitated at the lower hydrogen ion concentrations, that the iron of certain iron salts is less likely to be precipitated than that of others, and that certain salts of organic acids tend to keep the iron in solution. In general, ferric citrate seems to be the most favorable source of iron. In addition to chemical precipitation, however, it is also possible for the iron to be removed by adsorption on an amorphous precipitate such as calcium phosphate. As this precipitate is frequently formed when nutrient solutions are made alkaline, this may account for the discordant results reported in the literature as to the availability of certain forms of iron. By omitting calcium from the culture solution iron can be maintained in a form available for growth in alkaline solutions by the addition of sodium citrate. In such solutions the maximum growth of Chlorella occurred at pH 7.5. The alkaline limit for growth has not been established as yet.

In investigating the availability of iron at varying concentrations of the hydrogen ion, changes in the pH value of the solution during the course of an experiment should also be taken into account. This is especially important in unbuffered solutions. The differential absorption of the ions of ammonium salts may cause a marked increase in the hydrogen ion concentration, which in turn will cause an increase in the solubility of iron. In strongly buffered solutions as used in these experiments this effect is slight.
THE EFFECT OF RADIOACTIVE RADIATIONS AND X-RAYS ON ENZYMES
Authors: Hussey Raymond G. , Thompson William R.
Published: May 2004

The radiochemical inactivation of invertase by beta radiation from the radioactive products in equilibrium with radium emanation can be explained quantitatively on the same basis as that of trypsin and pepsin previously reported; namely, the rate of change in the logarithm of the concentration of the active enzyme with respect to the variable, W, is constant, under the conditions of irradiation described, when the volume of solution exposed is constant. When, within the limits stated in this paper, this volume (V) is varied, the rate of radiochemical change is inversely proportional to V; i.e.,

See PDF for Equation
THE EFFECT OF RADIATIONS FROM A MERCURY ARC IN QUARTZ ON ENZYMES
Authors: Hussey Raymond G. , Thompson William R.
Published: May 2004

Pepsin in solution is inactivated by the radiations from a mercury arc in quartz. It would seem that the effective radiations are those in the ultra-violet region of the spectrum. The form of the curve describing the course of the inactivation is the same as that found for monomolecular chemical change.
ACCUMULATION OF BRILLIANT CRESYL BLUE IN THE SAP OF LIVING CELLS OF NITELLA IN THE PRESENCE OF NH3
Authors: Irwin Marian
Published: May 2004

When the living cells of Nitella are placed in a solution of brilliant cresyl blue containing NH4Cl, the rate of accumulation of the dye in the sap is found to be lower than when the cells are placed in a solution of dye containing no NH4Cl and this may occur without any increase in the pH value of the cell sap. This decrease is found to be primarily due to the presence of NH3 in the sap and seems not to exist where NH3 is present only in the external solution at the concentration used.
THE PENETRATION OF CO2 INTO LIVING PROTOPLASM
Authors: Osterhout W. J. V. , Dorcas M. J.
Published: May 2004

The experiments indicate that little or no CO2 enters normal cells of Valonia except in the form of undissociated molecules.

Whenever the interior of a cell is more acid than the surrounding medium (excess base being the same in both) we may expect that at equilibrium the internal concentration of total CO2 will be less than the external.
THE EFFECT OF RADIOACTIVE RADIATIONS AND X-RAYS ON ENZYMES
Authors: Hussey Raymond G. , Thompson William R.
Published: May 2004

Data are presented which indicate that variation in temperature is associated with only slight variation in the speed of the radiochemical inactivation of pepsin in dilute solution.
CARBON DIOXIDE PRODUCTION AND DURATION OF LIFE OF DROSOPHILA CULTURES
Authors: Northrop John H.
Published: May 2004

The total CO2 produced by aseptic Drosophila cultures during the entire duration of life has been determined at 15°, 26°, and 30°C. in the dark and at 22–26°C. in the light.

The total amount of CO2 produced is not constant but is greater at 15° than at 26° or 30°, and is much greater in the light than in the dark.

The total duration of life, therefore, is not determined by the time required to produce a limiting amount of CO2.
THE DISSOCIATION CONSTANTS OF RACEMIC PROLINE AND CERTAIN RELATED COMPOUNDS
Authors: McCay C. M. , Schmidt Carl L. A.
Published: May 2004

1. It has been experimentally shown that breaking of the pyrrolidine ring of proline by nitrous acid is not a factor of sufficient magnitude to account for the amino nitrogen which is usually found in proline preparations.

2. A method for the preparation of racemic proline is described. The product was found to be free from amino nitrogen.

3. The dissociation constants of racemic proline and of certain structurally related compounds were determined.
ELECTROENDOSMOSIS THROUGH MAMMALIAN SEROUS MEMBRANES
Authors: Mudd Stuart
Published: May 2004

The rate of electroendosmotic flow through dog and cat pericardia is found to be proportional to the current strength. The plots of current strengths against volumes of liquid transported in unit time are, in the better experiments, straight lines passing through the origin; the slopes of the lines are characteristic of the several systems.

Data on transport rate with buffers of different specific resistances showed the following phenomena:

1. Decrease of the observed transport rate to a minimum between σ values of 95 and 60 ohms.

2. Changes in the membrane markedly affecting transport rate, at conductivities and osmotic pressures close to those of the blood.

3. Polarization of the membrane during the passage of current. The mean rate found for electroendosmotic transport across dog and cat serous membranes bathed in serum has been 0.19 to 0.30 (average, 0.25) c.mm. per minute per milliampere. The best experiments with dog serum and the living mesenteries of dogs under ether gave a mean rate of 0.29 c.mm. per minute per milliampere.

These data, together with data from other sources, are believed to indicate a probability approaching certainty that electroendosmotic effects are a factor in glandular secretion.
GALVANIC STIMULATION OF LUMINESCENCE IN PELAGIA NOCTILUCA
Authors: Moore A. R.
Published: May 2004

1. Pelagia noctiluca responds to galvanic stimulation by a luminescent glow at the anode. If placed near the cathode a secondary glow occurs also on the cathodal side.

2. The luminescent slime of Pelagia when subjected to the galvanic current glows around the cathode. This is referred partly to the movement of hydrogen bubbles, but in the main to the alkali formed at the cathode.

3. The cause of galvanic stimulation in Pelagia is ionic. (1) Anodal stimulation is referred to the blocking of positive ions by the tissue on that side. (2) Cathodal stimulation, when the animal lies near the cathode, is due to the diffusion of alkali outward from a region of high concentration (the cathode).

4. Only the margin of the bell is excited to luminescence by the galvanic current. It is therefore concluded that nervous elements are the seat of excitation.

5. Luminescence is not a result of muscular contraction, since K ion causes relaxation of musculature but a continuous luminescent glow in Pelagia. The galvanic current causes pulsations of the bell (contraction and relaxation of the musculature) but a continuous glow.
PHYSIOLOGICAL ONTOGENY
Authors: Murray Henry A.
Published: May 2004

1. The water, ash, glycogen, nitrogen, and ether extract content of the tissues of chicken embryos were determined between the 5th and the 19th days of incubation.

2. It was found that the concentration of solid substance changed from approximately 5 to 17 per cent during this interval. The chief change in the organic substances involved a relative decrease in the nitrogen as compared with the fat.

3. Bomb calorimetric estimations confirmed these findings. It was shown that the calorific value of the dried substance increased with age.

4. The rate of growth of the total solids, and of the potential energy of the tissues was estimated.

5 Various theoretical considerations were brought forward dealing chiefly with the order in which the chief organic substances, carbohydrate, protein, and fat could be ranged when judged by various criteria.
SPEED OF TOXIC ACTION OF ARSENIC IN THE SILKWORM
Authors: Campbell F. L.
Published: May 2004

A micro burette, micro pipette, and methods for their use in quantitative toxicological investigations on mandibulate insects are described.

It is suggested that the form of curves relating speed of toxic action to dosage may be explained by postulating suitable changes in rate of distribution, excretion, and cell penetration of poison as dosage varies.

The speed of toxic action of pentavalent arsenic in the silkworm is proportional to an integral power of the dosage at lower concentrations, and to a fractional power of the dosage at higher concentrations.
THE SALT ERROR OF INDICATORS CAUSED BY STANDARD ALKALINE BUFFERS THEMSELVES
Authors: McBain James W. , Dubois Olive E. , Hay Kathleen G.
Published: May 2004

1. It is found that with many indicators there is a big discrepancy between the true alkalinities or pH values of solutions of pure sodium hydroxide and of standard alkaline buffers which give the same actual colour. This discrepancy must be ascribed to salt error caused by the buffer itself and exceeds in the most extreme case two whole units of pH; that is, an error of 100 fold in determining alkalinity. In only three cases, namely alizarin yellow G, tropeolin O, and thymol violet, was this error inappreciable. Most of the thirty indicators tested were found for various reasons unsatisfactory in the alkaline range studied.

2. Several indicators show a maximum depth of colour after sufficient indicator has been added, but above a certain concentration further addition of indicator diminishes the colour again.
THE RESISTANCE OF LIVING ORGANISMS TO DIGESTION BY PEPSIN OR TRYPSIN
Authors: Northrop John H.
Published: May 2004

1. Pepsin and trypsin are quickly removed from solution by dead organisms. They are not able to penetrate into living organisms.

2. Trypsin injected into a living Amœba results in the death and disintegration of the cell.
A SYNTHETIC FOOD MEDIUM FOR THE CULTIVATION OF DROSOPHILA
Authors: Pearl Raymond
Published: May 2004

In this paper is described the composition and method of making a standard synthetic medium for the laboratory cultivation of Drosophila melanogaster.

It is shown that this medium is greatly superior to the banana medium commonly used for this purpose in respect of both the fertility and the mortality of flies kept on it. The range of superiority in respect of fertility is at different densities of population from about 48 per cent at the lowest, to 98 per cent at the highest densities experimentally reported here. The general experience of the laboratory with this medium, which frees experimental work on Drosophila from the incubus of the highly variable banana, shows it to have other points of superiority besides those discussed here.
REVERSAL OF PHOTOTROPISM IN DIEMYCTYLUS VIRIDESCENS
Authors: Stier T. J. B.
Published: May 2004

In its response to light of approximately 11.3 m.c. intensity Diemyctylus viridescens may be either positive or negative. Negative phototropism is characteristic of animals from which food has been withheld. Feeding suppresses this negative phototropism.
NOTE ON THE DISTRIBUTION OF CRITICAL TEMPERATURES FOR BIOLOGICAL PROCESSES
Authors: Crozier W. J.
Published: May 2004

The critical temperatures at which irregularities appear in the relations between vital processes and temperature are not distributed at random. As based upon detailed knowledge of individual cases, and as derived from inspection of the frequencies of occurrence, these critical points are usually found to be in the neighborhood of 4.5°, 9°, 15°, 20°, 25°, 27°, 30°.
MECHANISM OF THE ACCUMULATION OF DYE IN NITELLA ON THE BASIS OF THE ENTRANCE OF THE DYE AS UNDISSOCIATED MOLECULES
Authors: Irwin Marian
Published: May 2004

The rate of penetration of brilliant cresyl blue into the living cells of Nitella indicates that the dye enters only in the form of the undissociated molecule. At equilibrium the total concentration of the dye in the sap is proportional to the concentration of the free base in the outside solution.
THE EFFECTS OF CERTAIN HEAVY METALS ON RESPIRATION
Authors: Cook S. F.
Published: May 2004

1. The effect of the heavy metals on the respiration of Aspergillus niger is to cause the rate of carbon dioxide production to decrease from the first or to increase and subsequently diminish.

2. The speed of the toxic action varies as a constant power of the concentration.

3. The temperature coefficient of the toxic action is between 1.5 and 2.

4. An hypothesis is advanced to account for the action of the heavy metals, by means of which the experimental results may be accounted for. It is assumed that the metal is activated by a chemical combination with a cell constituent. This active compound alters the velocity constants of the normal respiratory reactions, and thus causes the observed changes in the rate of carbon dioxide production.
PHYSIOLOGICAL ONTOGENY
Authors: Murray Henry A.
Published: May 2004

The chief results of the studies here reported have been (1) the correlation between growth as a whole and the differentiation of gross form (primary redistributions or simple evolution), and (2) the correlation between internal integration or concentration and the differentiation of chemical form (secondary redistributions or compound evolution). With the latter are also associated the catabolic rate and the latent period or reaction time after implantation in plasma as demonstrated in tissue culture experiments. Moreover, it has been shown that these two chief developmental processes occur at different rates, and that they undergo their greatest changes in rate at different periods of embryonic life. Corresponding with Robertson's growth acceleration periods there may be three cycles or rhythms of which the embryonic phase is the first, each composed of a period of growth followed by a period of differentiation. This conception is somewhat analogous to Roux's notion of dividing the life span into two chief periods (1) embryonic for the growth of organ rudiments and (2) post-embryonic, characterized by functional development. The first period of total growth and form differentiation seems to cover the time when the main, but bare, outline or scaffolding of the organism is laid down. The second period, correlated as it is with catabolism (function), corresponds, not in time but as a phenomenon, with Roux's period of functional form development.
A LATENT PERIOD IN THE ACTION OF COPPER ON RESPIRATION
Authors: Cook S. F.
Published: May 2004

1. When copper chloride is allowed to act on Aspergillus niger there is at first a period during which there is no change in the rate of the production of carbon dioxide, following which the rate of respiration falls. The interval of no change is called the latent period.

2. When the copper is removed from the external solution before the end of the latent period this interval is prolonged. The rate of respiration then falls to a new level below the normal level.

3. Experiments on Nitella and on Valonia indicate that the copper penetrates the cell almost immediately.

4. The length of the latent period varies inversely as a constant power of the concentration of the copper.

5. These results are explained by assuming that the copper is made active in the respiration system by means of a reversible reaction. By using appropriate velocity constants the experimental curves can be duplicated by calculated curves.
STUDIES ON ENZYME ACTION
Authors: Noyes Helen Miller , Falk K. George , Baumann Emil J.
Published: May 2004

The ester-hydrolyzing actions of extracts of a number of tissues of rabbits of different ages were studied under comparable conditions.

The ages of the rabbits ranged from 8 days before birth to 2162 days. The esters used included phenyl acetate, glyceryl triacetate, methyl butyrate, benzyl acetate, methyl acetate, ethyl acetate, ethyl butyrate, methyl benzoate, ethyl benzoate, and isobutyl acetate. The following tissues were studied: kidney, liver, lung, skin, leg muscle, heart muscle, brain, spleen, stomach, and small intestine.

The results, as in previous communications, are presented in the form of plots for the relative enzyme actions, and in tables for the absolute actions.

The changes in the curves of the relative actions as the rabbits became older are considered in some detail. The relations between the embryonic state of certain tissues, as shown by their enzyme actions, and the adult state, are described, and compared with their physiological behavior. The probable reversion to a type approaching the embryonic for the oldest rabbits studied is indicated with some of the tissues. The changes in the absolute enzyme actions of the tissues as the rabbits became older are also discussed. The absolute actions do not form as regular a progression as do the relative actions but, at the same time, show marked regularities with increasing age of the rabbits.
THE KINETICS OF OSMOTIC SWELLING IN LIVING CELLS
Authors: McCutcheon Morton , Lucke Baldwin
Published: May 2004

The rate of swelling of unfertilized sea urchin eggs in hypotonic sea water was investigated. Analysis of curves leads to the following conclusions.

1. The rate of swelling follows the equation,

See PDF for Equation

where Veq., V0, and Vt stand for volume at equilibrium, at first instant, and at time t, respectively, the other symbols having their usual significance. This equation is found to hold over a wide range of temperatures and osmotic pressures. This relation is the one expected in a diffusion process.

2. The rate of swelling is found to have a high temperature coefficient (Q10 = 2 to 3, or µ = 13,000 to 19,000). This deviation from the usual effect of temperature on diffusion processes is thought to be associated with changes in cell permeability to water. The possible influence of changes in viscosity is discussed.

3. The lower the osmotic pressure of the solution, the longer it takes for swelling of the cell. Thus at 15° in 80 per cent sea water, the velocity constant has a value of 0.072, in 20 per cent sea water, of 0.006.
THE SIZE OF PORES IN COLLODION MEMBRANES
Authors: Hitchcock David I.
Published: May 2004

By the application of Poiseuille's law to the rate of flow of water through collodion membranes, it is calculated that the membranes used had pore radii of the order of 0.3 to 2 x 10–6 cm. On the same basis the number of pores per sq. cm. appears to vary from 270 x 1010 to 7 x 1010, decreasing with increase in pore size. Reasons are given for preferring these figures for the radii to figures, 100 times as large, which were calculated by others. Microscopic examination of the membranes, with dark-field illumination, indicates that they are made up of solid granules or filaments of collodion much less than 1 x 10–4 cm. in thickness.
DURATION OF LIFE OF AN ASEPTIC DROSOPHILA CULTURE INBRED IN THE DARK FOR 230 GENERATIONS
Authors: Northrop John H.
Published: May 2004

The number of pupæ formed per female, the duration of the larval period, and the duration of the pupal-imago period of a normal Drosophila culture and of the 230th generation of an aseptic culture which had been kept in the dark have been determined. The larval period and the pupal-imago period were found to be nearly the same for both cultures under both favorable and unfavorable conditions. There is no evidence, therefore, to show that inbreeding, absence of light, or growth in the absence of bacteria for 230 generations has had any effect either on the duration of life or on the ability of the organism to resist unfavorable bacteria.
PHYSIOLOGICAL ONTOGENY
Authors: Murray Henry A. ,   With the Assistance of Yetta Porosowsky.
Published: May 2004

1. The Arrhenius equation giving the relationship between the velocity of chemical reaction and temperature, was found suitable for the special case of the contraction rate of embryonic heart muscle fragments.

2. There was no constancy in the values of µ for the rate of contraction in culture, nor was the scattering evenly distributed around certain (more than one) points.

3. There seemed to be no correlation between µ and other functions such as the contraction rate, the site from which the piece was removed, the age of the embryo, etc.
EFFECT OF HIGH PRESSURE ON GERMINATION OF SEEDS (MEDICAGO SATIVA AND MELILOTUS ALBA)
Authors: Davies P. A.
Published: May 2004

An increase in percentage germination is obtained with seeds of Medicago sativa exposed for 1 to 10 minutes at 2000 atmospheres hydraulic pressure at 20°C., dried, and germinated after 30 days; and from seeds of Melilotus alba under the same conditions of pressure, when exposed for 5 to 30 minutes, dried, and germinated 30 days later. Exposures to 500 atmospheres pressure was less advantageous for germination; the vitality of seeds normally germinating was more rapidly destroyed than the hard impermeable seeds rendered permeable by the pressure treatment. At 0°C., it required approximately 2½ times the exposure to 2000 atmospheres for seeds of Medicago sativa, and approximately 5 times the exposure for seeds of Melilotus alba, as it did at 20°C.