bluuebunny/crossref_metadata_2025 huggingface dataset:
REACTIONS OF VALONIA AND OF HALICYSTIS TO COLLOIDS
Authors: East E. M. , White Benjamin
Published: May 2004

From the results of these tests it is clear that both Halicystis and Valonia have a high degree of tolerance for animal peptone, and a very high degree of tolerance for animal proteose and for egg albumen. The products of bacterial growths fostered by these proteins have a deleterious effect upon both species of algae; but, if it were possible to prevent bacterial growth entirely and at the same time supply proper food, it is probable that Halicystis and Valonia would show normal growth indefinitely in the presence of these three colloids. This is not true where exposure is made to yeast nucleic acid dissolved in sea water containing 0.00093 gm. per cc. of NaOH. Valonia is markedly less tolerant of this medium (perhaps of NaOH rather than the colloid used) than Halicystis. Such differential effects, however, reach a high point in the case of the solutions of diphtheria toxin and of edestin. Halicystis has a very high tolerance for diphtheria toxin, and Valonia a very low tolerance. In the case of edestin, the relationship is reversed. Here Halicystis has a very low tolerance, and Valonia a very high tolerance. In fact, it may be said that diphtheria toxin has no appreciable effect upon Halicystis, and edestin a very slight effect upon Valonia; while diphtheria toxin is extremely toxic to Valonia, and edestin is extremely toxic to Halicystis. We can offer no suggestions, at present, as to the way in which these effects are produced.

It is probable that the very thin protoplasmic layer of these species, which is certainly no thicker than 8µ, is sufficient to obstruct the passage of proteins having large molecules, like egg albumen, with a degree of efficiency that is extraordinary. In the tests we have reported, areas of from 20 sq. cm. to 40 sq. cm. have been submitted to the action of a relatively high concentration of egg albumen for several days without permitting the passage of sufficient amounts to give definable tests either with Spiegler's or with Tanret's method,— presumably less than 1 part in 250,000.

In the tests of the proteins having much smaller molecules (though the size may not be the explanation), there is some probability that the membranes exhibit a little permeability. The peptone and the proteose of animal origin, or biuret-positive substances derived from them, apparently pass the protoplasmic membranes occasionally in quantities sufficient to give biuret tests. The most probable case of protein passage, however, was that of the proteose of the scarlet runner bean, where specific detection of less than 1 part per 80,000 was possible. In this instance the proteose appeared to pass membranes that were healthy and were functioning normally. But since the cells of the algae had to be destroyed in making the tests, one cannot maintain this point. All one can say is that protein passage was indicated in carefully examined cells of both species, where no breaks in the protoplasmic membrane were discernible, and where samples of the treated cells behaved normally after treatment.
SWELLING OF ERYTHROCYTES IN SOLUTIONS OF AMMONIUM SALTS
Authors: Schiödt E.
Published: May 2004

Two rather simple equations have been derived, which make it possible to express in a single number the result of a series of determinations of the volume of erythrocytes swelling in solutions of ammonium salts.

In all experiments made with several combinations of different concentrations of permeating and non-permeating salts, the curves calculated from the equations have covered the points found by experiment.
REVERSIBLE LOSS OF THE POTASSIUM EFFECT IN DISTILLED WATER
Authors: Osterhout W. J. V. , Hill S. E.
Published: May 2004

Not only does distilled water take away the irritability of Nitella but it also changes its behavior toward potassium. In normal cells potassium is strongly negative to sodium but after sufficient exposure to distilled water this effect disappears. It can be restored by returning the cells to their normal environment or to a suitable nutrient solution. This change in the protoplasm seems to be chiefly in its outer surface.
PROTOPLASMIC POTENTIALS IN HALICYSTIS
Authors: Blinks L. R.
Published: May 2004

The nature and origin of the large "protoplasmic" potential in Halicystis must be studied by altering conditions, not only in external solutions, but in the sap and the protoplasm itself. Such interior alteration caused by the penetration of ammonia is described. Concentrations of NH4Cl in the sea water were varied from 0.00001 M to above 0.01 M. At pH 8.1 there is little effect below 0.0005 M NH4Cl. At about 0.001 M a sudden reversal of the potential difference across the protoplasm occurs, from about 68 mv. outside positive to 30 to 40 mv. outside negative. At this threshold value the time curve is characteristically S-shaped, with a slow beginning, a rapid reversal, and then an irregularly wavering negative value. There are characteristic cusps at the first application of the NH4Cl, also immediately after the reversal.

The application of higher NH4Cl concentrations causes a more rapid reversal, and also a somewhat higher negative value. Conversely the reduction of NH4Cl concentrations causes recovery of the normal positive potential, but the threshold for recovery is at a lower concentration than for the original reversal. A temporary overshooting or increase of the positive potential usually occurs on recovery. The reversals may be repeated many times on the same cell without injury.

The plot of P.D. against the log of ammonium ion concentration is not the straight line characteristic of ionic concentration effects, but has a break of 100 mv. or more at the threshold value. Further evidence that the potential is not greatly influenced by ammonium ions is obtained by altering the pH of the sea water. At pH 5, no reversal occurs with 0.1 M NH4Cl, while at pH 10.3, the NH4Cl threshold is 0.0001 M or less. This indicates that the reversal is due to undissociated ammonia.

The penetration of NH3 into the cells increases both the internal ammonia and the pH. The actual concentration of ammonium salt in the sap is again shown to have little effect on the P.D. The pH is therefore the governing factor. But assuming that NH3 enters the cells until it is in equilibrium between sap and sea water, no sudden break of pH should occur, pH being instead directly proportional to log NH3 for any constant (NH4) concentration. Experimentally, a linear relation is found between the pH of the sap and the log NH3 in sea water. The sudden change of P.D. must therefore be ascribed to some system in the cell upon which the pH change operates. The pH value of the sap at the NH3 threshold is between 6.0 and 6.5 which corresponds well with the pH value found to cause reversal of P.D. by direct perfusion of solutions in the vacuole.
SOME METHODICAL ERRORS WHICH MAY ARISE IN THE DETERMINATION OF BOUND WATER
Authors: Bull Henry B.
Published: May 2004

The "bound water" hypothesis has an adequate theoretical basis. A relatively slight adsorption of the solute along with water molecules (bound water) will explain the failure of certain technics to demonstrate the existence of bound water in biochemical systems.
ANESTHESIA PRODUCED BY DISTILLED WATER
Authors: Osterhout W. J. V. , Hill S. E.
Published: May 2004

Cells of Nitella flexilis Ag. lose their power to respond to ordinary electrical stimulation after 2 or 3 days in distilled water. It returns after a day or so when they are replaced in their normal environment, in a suitable nutrient solution, or in a dilute solution of CaCl2.

Here anesthesia seems to be produced by removing something from the cell and this raises the question whether other cases of anesthesia may be explained in the same way.

The antagonistic action of calcium, in some cases at least, appears to depend on its power to prevent substances from leaching out of the cell.
ANESTHESIA IN ACID AND ALKALINE SOLUTIONS
Authors: Osterhout W. J. V. , Hill S. E.
Published: May 2004

The action of distilled water in producing anesthesia (loss of response to electrical stimulation) in Nitella is hastened by the addition of acid and alkali and retarded by the addition of calcium. The loss of irritability is fully reversible.
THE ESTIMATION OF ACTIVE NATIVE TRYPSIN IN THE PRESENCE OF INACTIVE DENATURED TRYPSIN
Authors: Anson M. L. , Mirsky A. E.
Published: May 2004

Inactive denatured trypsin changes into active native trypsin in the protein solutions which have been used to estimate tryptic activity. If the digestion mixture, however, is alkaline enough and contains enough urea this change does not take place. Such a digestion mixture can be used to estimate active native trypsin in the presence of inactive denatured trypsin.
THE CRYOSCOPIC METHOD FOR THE DETERMINATION OF "BOUND WATER"
Authors: Gortner Ross Aiken , Gortner Willis Alway
Published: May 2004

1. The criticisms by Grollman (7) of the cryoscopic method for the determination of bound water as proposed by Newton and Gortner (1) have been considered, and it is pointed out that even admitting the correctness of his contentions does not negative the conclusion that bound water values as determined by the cryoscopic method parallel in a remarkable manner the physiological responses of plants to environmental conditions.

2. A new method of calculating the true freezing point of a solution is proposed.

3. Gum acacia in aqueous sucrose solutions shows positive amounts of bound water to the extent of 0.6 to 0.7 gm. of bound water per gram of gum.

4. Gum acacia in aqueous solutions of KCl and KBr shows slightly negative amounts of bound water, indicating a preferential adsorption of the solute rather than the solvent.
THE INFLUENCE OF THE MOLECULAR WEIGHT ANTIGEN ON THE PROPORTION OF ANTIBODY TO ANTIGEN IN PRECIPITATES
Authors: Boyd William C. , Hooker Sanford B.
Published: May 2004

The assumption that, at the equivalence point in specific precipitin reactions, the antigen molecule is completely covered with a single layer of antibody-globulin molecules has been shown to account fairly well for the antibody-antigen ratios of some representative native single proteins, and the pneumococcus S III hapten.
CRYSTALLINE PEPSIN
Authors: Northrop John H.
Published: May 2004

1. The loss in activity of crystalline pepsin solutions when exposed to beta and gamma rays from radium or to ultra-violet light is accompanied by a corresponding decrease in pepsin protein.

2. The rate of inactivation by ultra-violet light depends upon the pH and is a maximum at about pH 2.0.
A NOTE ON THE RESPIRATION OF ARBACIA EGGS
Authors: Gerard R. W. , Rubinstein B. B.
Published: May 2004

Methods used in preparing Arbacia eggs for respiration studies, in carrying through the manometric determinations, and in estimating egg quantities have been reexamined.

Discrepancies in previous results are almost entirely due to a steady error in measuring egg volume by centrifuging. Volumes so obtained averaged 80 per cent too high.

The respiration of unfertilized eggs of Arbacia punctulata at 21°C. is 0.9 c.mm. O2 per hour per 10 c.mm. of eggs.
THE EQUILIBRIUM BETWEEN ACTIVE NATIVE TRYPSIN AND INACTIVE DENATURED TRYPSIN
Authors: Anson M. L. , Mirsky A. E.
Published: May 2004

There is a mobile equilibrium between the native and denatured forms of trypsin which depends on the concentrations of acid, alkali, and alcohol and on the temperature.

The heat of denaturation in 0.01 N hydrochloric acid calculated from the effect of temperature on the equilibrium constant is –67,600 calories per mole.
THE VISUAL ACUITY AND INTENSITY DISCRIMINATION OF DROSOPHILA
Authors: Hecht Selig , Wald George
Published: May 2004

Drosophila possesses an inherited reflex response to a moving visual pattern which can be used to measure its capacity for intensity discrimination and its visual acuity at different illuminations. It is found that these two properties of vision run approximately parallel courses as functions of the prevailing intensity.

Visual acuity varies with the logarithm of the intensity in much the same sigmoid way as in man, the bee, and the fiddler crab. The resolving power is very poor at low illuminations and increases at high illuminations. The maximum visual acuity is 0.0018, which is 1/1000 of the maximum of the human eye and 1/10 that of the bee.

The intensity discrimination of Drosophila is also extremely poor, even at its best. At low illuminations for two intensities to be recognized as different, the higher must be nearly 100 times the lower. This ratio decreases as the intensity increases, and reaches a minimum of 2.5 which is maintained at the highest intensities. The minimum value of ΔI/I for Drosophila is 1.5, which is to be compared with 0.25 for the bee and 0.006 for man.

An explanation of the variation of visual acuity with illumination is given in terms of the variation in number of elements functional in the retinal mosaic at different intensities, this being dependent on the general statistical distribution of thresholds in the ommatidial population. Visual acuity is thus determined by the integral form of this distribution and corresponds to the total number of elements functional. The idea that intensity discrimination is determined by the differential form of this distribution—that is, that it depends on the rate of entrance of functional elements with intensity—is shown to be untenable in the light of the correspondence of the two visual functions. It is suggested that, like visual acuity, intensity discrimination may also have to be considered as a function of the total number of elements active at a given intensity.
THE POTASSIUM EQUILIBRIUM IN MUSCLE
Authors: Fenn Wallace O. , Cobb Doris M.
Published: May 2004

1. Analyses were made of the K and HCO3 content, the irritability, and weight change of isolated frog sartorius muscles after immersion for 5 hours in Ringer's solutions modified as to pH and potassium content.

2. At each pH a concentration of potassium in the solution was found which was in diffusion equilibrium with the potassium in the muscle. In greater concentrations potassium moved into the muscle against the concentration gradient and vice versa.

3. The greater the alkalinity of the solution the smaller the concentration of the potassium at equilibrium so that the product of the concentrations of OH and K in the solution at equilibrium tends to remain approximately constant.

4. The pH inside the muscle is approximately equal to that outside when first dissected but it tends to change during immersion so as to follow the changes in the pH of the solution. This finding is in direct conflict with the theory according to which the high potassium concentration inside should be accompanied by an equally high hydrogen ion concentration in relation to that outside.

5. The diffusion of potassium into the muscle makes its contents more alkaline but the increase in alkalinity is not always, nor usually, equivalent to the amount of potassium which has diffused and conversely, the pH inside can change in either direction according to the pH outside without there being any diffusion of potassium. Hence potassium is not the only penetrating ion.

6. The irritability of the muscles is at a maximum in concentrations of potassium which are greater than that in normal Ringer's solution, or about 20 mg. per cent potassium. This optimum does not seem to be a function of pH and is therefore not dependent upon the direction of movement of the potassium but probably on the ratio of potassium outside to that inside.

7. Swelling of the muscles occurs in solutions which injure the muscle so as to permit both cations and anions to enter without permitting the organic protein anions to escape. Anion impermeability is necessary to prevent this same osmotic swelling under normal conditions.

8. An increase in the CO2 tension in muscle and solution causes a greater increase in acidity in the solution than in the muscle and leads to a loss of potassium. One expects therefore a potassium shift from tissues to blood comparable to the chlorine shift from plasma to corpuscles.
THE DIFFUSION OF CARBON DIOXIDE IN TISSUES
Authors: Wright Charles I.
Published: May 2004

1. Two methods are given for measuring the rate of diffusion of CO2 in tissue membranes. Methods are also given for the determination of tissue thickness and the absorption coefficient for CO2 in tissues.

2. The values obtained for the permeability constant (P x 104) at 22°C. for CO2 in the following tissues are:—frog skin, 3.05; connective tissue (dog), 2.65; smooth muscle (cat), 5.00; frog muscle, 5.29; striated muscle (dog), 4.70. P is expressed as cc. per cm.2 per minute under a pressure gradient of one atmosphere per cm.

3. Evidence is presented to show that in a "steady state" bicarbonate contributes a negligible amount to the diffusion of CO2.

4. The absorption coefficient for CO2 in frog skin is 0.73 cc. per cc. and for frog muscle 0.78 cc. per cc.

5. In all of the tissues studied the diffusion of CO2 is slower than in water. The diffusion coefficients (K x 104 in cm.2/minute) at 22°C. for tissues as compared with water are:—water (16°C.), 9.5 (Hüfner, 1897); frog skin, 4.1; connective tissue, 3.7; frog muscle, 6.8; striated muscle (dog), 6.0; smooth muscle (cat), 6.4.

6. The time course of saturation of a tissue with CO2 is altered in the presence of available base. Non-acidified tissues saturate more slowly than acidified tissues and the rate of saturation is dependent on the CO2 tension.
FERTILIZATION AND THE TEMPERATURE COEFFICIENTS OF OXYGEN CONSUMPTION IN EGGS OF ARBACIA PUNCTULATA
Authors: Rubenstein B. B. , Gerard R. W.
Published: May 2004

The eggs of A. punctulata have a high temperature coefficient in the resting state: Q10 = 4.1.

On fertilization and on cytolysis the temperature coefficient falls to less than half the resting value: Q10 = 1.8 and 1.9 respectively.

The factor by which oxygen consumption increases on fertilization is a variable, its magnitude depending on temperature as well as on egg species. It is nearly ten times greater at 11°C. and only double at 29.9°C. By extrapolating to 32°C. there would be no increase on fertilization.

Critical thermal increments common to many oxidations, 6,500, 10,800, and 12,500, have been found.

The possible significance of these results is discussed in relation to the catalytic mechanisms and structural organization of the egg cell.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G. , Osterhout W. J. V.
Published: May 2004

It would be natural to suppose that potassium enters Valonia as KCl since it appears in this form in the sap. We find, however, that on this basis we cannot predict the behavior of potassium in any respect. But we can readily do so if we assume that it penetrates chiefly as KOH. We may then say that under normal conditions potassium enters the cell because the ionic activity product (K) (OH) is greater outside than inside. This hypothesis.leads to the following predictions:

1. When the product (K) (OH) becomes greater inside (because the inside concentration of OH- rises, or the outside concentration of K+ or of OH- falls) potassium should leave the cell, though sodium continues to enter. Previous experiments, and those in this paper, indicate that this is the case.

2. Increasing the pH value of the sea water should increase the rate of entrance of potassium, and vice versa. This appears to be shown by the results described in the present paper.

It appears that photosynthesis increases the rate of entrance of potassium by increasing the pH value just outside the protoplasm. In darkness there is little or no growth or absorption of electrolytes.

The entrance of potassium by ionic exchange (K+ exchanged for H+ produced in the cell), the ions passing as such through the protoplasmic surface, does not seem to be important.
TEMPERATURE CHARACTERISTICS FOR METABOLISM OF CHLORELLA
Authors: Crozier W. J. , Tang P. S. , French C. S.
Published: May 2004

The temperature characteristic for the rate of O2 consumption by Chlorella pyrenoidosa suspended in Knop solution containing 1 per cent glucose was studied between 1° and 27°C. with the Warburg technic. The value of µ was found to be about 19,000 ±1,000 cal. There is some indication of a critical temperature at 20°C., with shift to a lower µ above this temperature. The effect of sudden changes in temperature on the rate of respiration and the variation of the latter with time at constant temperatures are discussed. It is concluded that the "normal" respiration (in absence of external glucose) does not appear in the determination of this temperature characteristic.
RESULTS OF IRRADIATING SACCHAROMYCES WITH MONOCHROMATIC ULTRA-VIOLET LIGHT
Authors: Oster Robert H.
Published: May 2004

Effects of measured ultra-violet light on the yeast S. cerevisiae have been studied. Methods of culturing and irradiating the yeast, of estimating the nature and extent of the changes produced, and the means used in producing and measuring the radiation are given.

No evidence of a stimulative action was observed. The absorbed energy did not produce an all or none effect; arbitrary criteria must be used for judging the various inhibitory and lethal effects. With increase in the incident energy diverse effects were produced until abnormal cell growth and "death" of the cells resulted. Changes in the rate of oxygen consumption did not occur until after a high proportion of the irradiated cells were so damaged that they produced abnormal cells.

The shape of the curves relating effect to energy are similar for various wave-lengths but different energies are required to produce the same effect at each of the wave-lengths studied. The similarity of the curves to that for a first order reaction is noted, but attention is called to the modifying influence of accessory factors such as the age of the cells. A comparison is made of the morphological and metabolic changes on the basis of energy requirements, and their relative value as criteria in judging the effects of ultra-violet light on yeast and physiologically similar microorganisms.
ON THE THEORETICAL SIGNIFICANCE OF TALBOT'S LAW
Authors: Arnold William , Winsor C. P.
Published: May 2004

On the assumptions (1) that the state of the photoreceptor is completely determined by its previous history in respect of exposure to light, (2) that photoreception involves two opposed processes, one of which is light-sensitive, and (3) that sensation is determined by the rate of the light-sensitive process integrated over a short period, it is shown that Talbot's law has as a necessary consequence that the velocity of the light-sensitive process must be directly proportional to the intensity of the stimulating light.
TEMPERATURE CHARACTERISTICS FOR THE METABOLISM OF CHLORELLA
Authors: French C. S. , Kohn H. I. , Tang P. S.
Published: May 2004

The respiration of the green alga Chlorella pyrenoidosa, suspended in Knop's solution, has been studied in the dark as a function of time and of temperature. The rates of oxygen consumption and of carbon dioxide production (at constant temperature) decline for about 25 hours to a low, constant level. From an analysis of the curves it is suggested that two substances, A and B, are utilized, whose respiratory quotients are 1 and 0.65 respectively. The values of the temperature characteristics were found to be: for oxidation of A, 19,500 (0.6 to 11.5°C.) and 3,500 (11.5 to 28°C.); for oxidation of B, 5,600 (23.4 to 0.6°C.).
ADAPTATION OF CUTANEOUS TACTILE RECEPTORS. II
Authors: Hoagland Hudson
Published: May 2004

Studies of axon potentials set up by pressure stimuli applied to single cutaneous receptors in frog's skin indicate that the mechanical stimulus excites the free nerve endings directly.

Adaptation to constant pressures or to intermittently applied pressures (failure of the response) may be due to the reduction of excitability of the nerve endings by potassium released under the pressure from surrounding epithelial cells.
THE TEMPERATURE COEFFICIENT OF INACTIVATION OF CRYSTALLINE PEPSIN BY ULTRA-VIOLET RADIATION
Authors: Gates Frederick L.
Published: May 2004

Determinations of the temperature coefficient of inactivation of pure crystalline pepsin solutions by ultra-violet irradiation give values very close to unity (1.02).
POSITIVE VARIATIONS IN NITELLA
Authors: Osterhout W. J. V. , Hill S. E.
Published: May 2004

The reversible electrical variations hitherto described for plants and animals consist in a reversible loss of positive potential at a stimulated spot by which it becomes more negative.

In this paper we describe changes which consist in a reversible loss of negative potential at a stimulated spot whereby it becomes more positive. We suggest that this be called a positive variation.

The stimulation was produced in all cases by pinching or bending the cell. This produced a compression wave which traveled along the cell, producing a negative variation at a spot which was positive and a positive variation at a spot which was negative (due to application of 0.1 M KCl).

The response produced by the compression wave differs in several respects from an ordinary propagated negative variation and may be termed a positive mechanical variation.
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Hill S. E. , Osterhout W. J. V.
Published: May 2004

The action curve involves four movements each of which shows considerable variation. These variations can be accounted for on the assumption that the action curve is due to the movement of potassium ions accompanied by an increase in permeability.
PROTOPLASMIC POTENTIALS IN HALICYSTIS
Authors: Blinks L. R.
Published: May 2004

Perfusion of the vacuole of living cells of Halicystis is described, the method employing two longitudinally fused capillaries as entrance and exit tubes. Natural sap, artificial sap, and sea water have been successfully perfused, with various additions and deficiencies, within the limits of physiological balance.

In H. ovalis the P.D. remains positive and scarcely reduced in value when normal sea water, at pH 8.1, is perfused in the vacuole. In H. Osterhoutii the P.D. reverses in sign when the perfused solution has a higher pH than 6.5. In both cases a large P.D. persists when the solutions are the same on both sides of the protoplasm. In the absence of external gradients, there must be some internal gradient or asymmetry of the protoplasm itself to account for the P.D. Since appreciable currents are produced, there must be some metabolic activity as a source of energy.

The higher normal P.D. in H. ovalis is not due to the higher KCl content of its sap (as earlier suggested by the author) since it persists nearly unchanged when sea water is substituted for sap.
A METHOD FOR DETERMINING THE RENNET ACTIVITY OF CHYMO-TRYPSIN
Authors: Kunitz M.
Published: May 2004

The rennet activity of chymo-trypsin (or pepsin) is conveniently measured by allowing a standard solution of milk to which chymotrypsin has been added to flow slowly through a graduated pipette and observing the rate and distance of flow of the milk before it clots. The time required for chymo-trypsin to clot milk may be calculated from these observations. The rennet activity is expressed as the reciprocal of the time in minutes required for 1 ml. of enzyme solution to clot 10 ml. of standard milk powder solution.
THE CONDUCTIVITIES OF AQUEOUS SOLUTIONS OF GLYCINE, d,l-VALINE, AND l-ASPARAGINE
Authors: Mehl John W. , Schmidt Carl L. A.
Published: May 2004

1. The conductivities of aqueous solutions of glycine, d,l-valine, and l-asparagine have been determined, and comparisons have been made with similar data reported in the literature.

2. On the basis of certain theoretical considerations, calculations of the expected conductivities of aqueous solutions of glycine, asparagine, aspartic acid, and glutamic acid have been made and these data have been compared with similar data obtained experimentally.

3. The dissociation constants of the carboxyl groups of aspartic acid and glutamic acid have been calculated from conductivity data.

4. It is shown that alanine has no effect on the ionic atmosphere of solutions of potassium chloride.
OSMOTIC RELATIONSHIPS IN THE HEN'S EGG AS DETERMINED BY RELATIVE VAPOR PRESSURES
Authors: Johlin J. M.
Published: May 2004

It has been shown by a comparison of the relative vapor pressures of egg yolk and egg white before and after the addition of sodium chloride to the white that the osmotic pressure of the yolk is greater than that of the white.
A PHYSICAL-CHEMICAL DIFFERENCE IN ANTIBODIES AGAINST THE S AND R VARIANTS OF A SINGLE BACTERIAL STRAIN
Authors: Joffe Eleanore W.
Published: May 2004

1. Rabbits were immunized with Bact. typhosum 0 901 S and 0 901 R, over a long period. Homologous and heterologous strains were sensitized with sera obtained from weekly bleedings. Agglutination titer was recorded, and the isoelectric points of the bacteria maximally sensitized were determined.

2. 0 901 S maximally sensitized with homologous immune serum had isoelectric points which became more alkaline as immunization progressed, covering a range of pH 4.8 to 5.5.

3. Strain 0 901 R maximally sensitized with homologous immune serum had isoelectric points which became more alkaline as immunization progressed, covering the range of pH 5.0 to 5.9.

4. Both 0 901 S and 0 901 R maximally sensitized with heterologous serum had isoelectric points lower than when sensitized with homologous serum.

5. The isoelectric points of both forms sensitized with increasing concentrations of homologous immune serum were determined. Increasing concentrations of homologous immune serum shifted the isoelectric point of 0 901 R from less than 2.2 for the unsensitized bacteria progressively to the alkaline side until the maximum values previously mentioned were reached. Increasing concentrations of homologous immune serum conferred upon 0 901 S isoelectric points which became only slightly more alkaline in maximal sensitization.

6. The electrophoretic mobilities of 0 901 S and 0 901 R, in each case maximally sensitized with homologous hyperimmune serum, were found to differ significantly over the whole range of pH studied.
THE THEORY OF DIFFUSION IN CELL MODELS
Authors: Longsworth Lewis G.
Published: May 2004

The differential equations describing diffusion in cell models have been extended to include the simultaneous penetration of water and two salts. These equations have been solved for the steady state. Values for the concentrations in the steady state which may be computed from the equations compare favorably with the experimental values obtained by Osterhout, Kamerling, and Stanley. Moreover, it has been shown elsewhere that the solution for the steady state is essential to a discussion of the volume change or "growth" of phase C in the models and, by analogy, in living cells.
THE EFFECTS OF RADIATIONS ON BIOLOGICAL SYSTEMS
Authors: Hussey Raymond , Thompson William R.
Published: May 2004

By means of measurement of CO2 respiratory rates it has been possible to observe immediate and latent effects of x-ray irradiations upon Drosophila larvae. The observations were extended over a period of several days, the duration of the prepupal period being observed also. In every instance a significant decrease in the rate of CO2 respiration was observed immediately after irradiation. This decrease was univariant with the period of irradiation within the experimental limits.
THE GEOTROPIC RESPONSE IN ASTERINA
Authors: Crozier W. J.
Published: May 2004

Upon a surface inclined at angle α Asterina gibbosa orients upward during negatively geotropic creeping until the average angle (θ) of the path is such that Δ sin θ/Δ sin α = const. This is true also in positively geotropic movement. The direction of orientation may be temporarily reversed by mechanical disturbance. The variation of θ is greater at low slopes. Tests with directed impressed pulls, due to an attached cork float, show that the pull upon the tube feet is of primary consequence for the determination of θ. When the component of gravitational pull in the direction of movement reaches a fraction of the total pull which is proportional to the gravitational vector parallel to the surface, the laterally acting component is ineffective. On this basis, it follows that Δ sin θ/Δ sin α = const.
ON REVERSAL OF GEOTROPISM IN ASTERINA
Authors: Crozier W. J.
Published: May 2004

A certain level of strychninization induces in Asterina reversal of geotropism from the normally geonegative movement to a persistent downward creeping. The effect of an attached float producing upward pull is to induce upward creeping, under these conditions, whereas normally it leads to downward movement. This reversal cannot be regarded as due to a mere intensification of the sensory effect of tension. It must be understood as representing a true reversal of inhibition. The temporary reversal of geotropism following mechanical disturbances (in the absence of strychnine) is interpreted in the same way.
A THEORY OF VISUAL INTENSITY DISCRIMINATION
Authors: Hecht Selig
Published: May 2004

1. A theory of visual intensity discrimination is proposed in terms of the photochemical events which take place at the moment when a photosensory system already adapted to the intensity I is exposed to the just perceptibly higher intensity I+ΔI. Unlike previous formulations this theory predicts that the fraction ΔI/I, after rapidly decreasing as I increases, does not increase again at high intensities, but reaches a constant value which is maintained even at the highest intensities.

2. The theory describes quantitatively the intensity discrimination data of Drosophila, of the bee, and of Mya.

3. With some carefully considered exceptions the intensity discrimination data of the human eye fall into two classes: those with small test areas or with red light, which form a single continuous curve describing the function of the retinal cones alone, and those with larger areas, and with white, orange, and yellow light, which form a double curve showing a clear inflection point, and represent the separate function of the rods at intensities below the inflection point and of the cones at intensities above it.

4. The theory describes all these data quantitatively by treating the rods and cones as two independently functioning photosensory systems in accordance with the well established duplicity idea.

5. In terms of the theory the data of intensity discrimination give critical information about the order of both the photochemical and dark reactions in each photosensory system. The reactions turn out to be variously monomolecular and bimolecular for the different animals.
ON THE MODIFICATION OF TEMPERATURE CHARACTERISTICS. I
Authors: Crozier W. J.
Published: May 2004

The temperature characteristics for frequency of pulsation in isolated cloacal ends of Holothuria tubulosa are µ = 20,400 from 10 to 20°, 8,000 from 20 to 30°. The critical temperatures 10°, 20°, 30° are related to thermal conditions in the environment.

In sea water with doubled NaCl content µ = 8,000 from 10 to 30°. This is consistent with the specific nature of the temperature characteristics.

The primary effect of increased NaCl is to alter the temperature characteristic curve. At low temperatures the frequency is increased, at higher temperatures diminished. The effect upon frequency is thus of less significance. It is pointed out that such relationships must be taken into account in analyzing the action of reagents upon organisms.
STUDIES ON BLOOD COAGULATION
Authors: Eagle Harry
Published: May 2004

Despite their reported stability, the platelets of hemophilic blood function normally. The prothrombin content of such plasma is also normal. Confirming the findings of Addis, the delayed coagulation observed in hemophilic blood is due to an unexplained retarded activation of prothrombin to thrombin. The addition of an excess of platelets, whether normal, hemophilic, or animal in origin, accelerates thrombin production and makes hemophilic blood clot normally; but cephalin, despite the fact that it accelerates thrombin production in normal plasma, is unexplainedly ineffective when added to hemophilic plasma.
CORRELATION OF THE VISCOSITIES OF PROTEIN SOLUTIONS WITH THEIR ABILITY TO CRYSTALLIZE
Authors: Hand David B.
Published: May 2004

All the proteins whose viscosities in solution have been measured fall distinctly into two classes. Proteins of viscosity equal to and lower than serum albumin are readily crystallized. Proteins with viscosity equal to or greater than denatured ovalbumin have not yet been crystallized.
THE VALIDITY OF TALBOT'S LAW FOR THE EYE OF THE HONEY BEE
Authors: Wolf Ernst , Zerrahn-Wolf Gertrud
Published: May 2004

By presenting to bees two illuminated fields, equal in brightness, of which one is flickering and the other stationary we find that on account of the bee's positive phototropic response equal numbers of bees travel to both fields. We thus can assume that Talbot's law is valid for the eye of the bee.
THE EFFECTS OF RADIATIONS ON BIOLOGICAL SYSTEMS
Authors: Thompson William R.
Published: May 2004

1. Although ultraviolet irradiation of larvae did not prolong the larval stage as is the case with x-rays, the immediate effects on respiratory rates are strikingly similar.

2. Effects of irradiation at different ages were observed and also effects of successive irradiations with remarkable agreement in comparable lots.
ELECTRIC IMPEDANCE OF HIPPONOË EGGS
Authors: Cole Kenneth S.
Published: May 2004

Alternating current resistance and capacity measurements have been made from 1.08 103 to 2.32 106 cycles per second on suspensions of unfertilized, fertilized, and swollen unfertilized eggs of the echinoderm Hipponoë esculenta. A simple method has been developed for measuring the volume concentration of eggs in a suspension.

The membrane of the unfertilized egg is practically non-conducting at low frequencies and shows a static capacity of 0.87 µf/cm.2 except perhaps at the highest frequencies. The equivalent specific resistance of the egg interior is 11 times that of sea water.

The membrane of the fertilized egg is practically non-conducting at low frequencies and shows a static capacity 2.5 times that of the unfertilized egg except at the higher frequencies where another reactive element produces a marked effect. The internal resistance is apparently higher than that of the unfertilized egg.

The static capacity per unit area of the membrane decreases as a linear function of the surface area when the eggs are swollen in dilute sea water. In 40 per cent sea water, the capacity falls to about 75 per cent of normal.
THE SIGNIFICANCE OF THE STRUCTURE OF A MEMBRANE FOR ITS SELECTIVE PERMEABILITY
Authors: Wilbrandt W.
Published: May 2004

The attempt is made to reconcile the two existing theories on the mechanism of selective ion permeability of the cell membrane by taking into account the molecular arrangement in the substance of the membrane. It is shown that the pore theory and the solubility theory are not contradictory, but two aspects of the same problem, one from the thermodynamic point of view, the other from the point of view of molecular theory.

The dried collodion membrane is used as a model in these studies. Its different behavior towards anions and cations is explained on the ground of a quasi-crystalline structure of collodion, the NO3-groups acting as dipoles with the negative charge directed towards the intermolecular spaces, no matter whether these pores are of molecular dimensions or larger. In this way a continuity in the behavior of the ordinary large pored collodion membrane and the dried membrane is established, both theoretically and experimentally. Experiments, with membranes of other cellulose derivatives agree with the mechanism suggested. Membranes of cellophane and ethyl cellulose are negatively charged, membranes of cellulose acetate positively.

From solutions of collodion mixed with basic dyestuffs or alkaloids membranes can be obtained more permeable to anions than to cations in contrast to the ordinary collodion membrane. Membranes can be built which give high potential differences even between two identical electrolyte solutions. The asymmetry lies here within the membrane and is artificially produced by gluing together an ordinary collodion membrane with one previously impregnated with a basic dyestuff or an alkaloid.
THE KINETICS OF PENETRATION
Authors: Jacques A. G. , Osterhout W. J. V.
Published: May 2004

The rate of entrance of potassium into Nitella flexilis has been investigated, and it has been shown that (a) at the concentrations studied the rate is independent of the external pH between 6 and 8 but it is possible that at lower concentrations a dependence may be found; (b) that it does not vary much with the external potassium concentration between 0.01 and 0.001 M, but appears to vary more with the potassium concentration below this limit.

It has also been shown that the rate is independent of the illumination, in contrast with the penetration of halides into Nitella clavata studied by Hoagland.

It has been found that potassium leaves the cells in distilled water, and since this does not seem to be the result of injury, there is apparently a concentration between 0 and 0.0001 M at which potassium neither enters nor leaves the cell. In Valonia increase of external potassium increases the rate of entrance as shown in the increase in moles of potassium in the sap. In Nitella this is true below an external concentration of 0.001 M. In Valonia this increase is paralleled by the increase in entrance of water so that little or no change in concentration occurs, but in Nitella no growth occurred during the experiment and in consequence the concentration of potassium in the sap increased.

It has been shown that the potassium content of the raw gelatinous sap is no greater than that of its ultrafiltrate, so that it is not possible to assume that any of the potassium is bound up in the cell in colloidal compounds.

It has been pointed out that all the gradients between the sap and the external solution are unfavorable to the entrance of potassium except the potassium bicarbonate gradient. However, on other grounds entrance as potassium bicarbonate is not considered to be very probable.

Various modes of entrance are discussed and it has been concluded that the subject must be investigated further before a definite answer can be given.
STUDIES ON OSMOTIC EQUILIBRIUM AND ON THE KINETICS OF OSMOSIS IN LIVING CELLS BY A DIFFRACTION METHOD
Authors: Lucké Balduin , Larrabee Martin G. , Hartline H. Keffer
Published: May 2004

1. Osmotic equilibrium and kinetics of osmosis of living cells (unfertilized eggs of Arbacia punctulata) have been studied by a diffraction method. This method consists of illuminating a suspension of cells by parallel monochromatic light and measuring, by means of telescope and scale, the angular dimensions of the resulting diffraction pattern from which the average volume of the cells may be computed.

The method is far less laborious and possesses several advantages over direct measurement of individual cells. The average size of a large number of cells is obtained from a single measurement of the diffraction pattern and thus individual variability is averaged out. The observations can be made at intervals of a few seconds, permitting changes in volume to be followed satisfactorily. During the measurements the cells are in suspension and are constantly stirred.

2. Volumes of cells in equilibrium with solutions of different osmotic pressure have been determined. In agreement with our previous experiments, based upon direct microscope measurements, we have confirmed the applicability of the law of Boyle-van't Hoff to these cells; that is to say, the product of volume and pressure has been found to be approximately constant if allowance be made for the volume of osmotically inactive material of the cell contents.

The volume of osmotically inactive material was found to be, on the average, 12 per cent of the initial cell volume; in eggs from different animals this value ranged from 6 to 20 per cent.

3. Permeability to water of the Arbacia egg has been found to average, at 22°C., 0.106 cubic micra of water per square micron of cell surface, per minute, per atmosphere of difference in osmotic pressure.

4. Permeability to ethylene glycol has been found to average, at 24°C., 4.0 x 10–15 mols, per square micron of cell surface, per minute, for a concentration difference of 1 mol per liter. This is in agreement with the values reported by Stewart and Jacobs.
INHIBITION OF PHOTOSYNTHESIS IN CHLORELLA PYRENOIDOSA BY THE IODO-ACETYL RADICAL
Authors: Kohn Henry I.
Published: May 2004

Photosynthesis in Chlorella pyrenoidosa is inhibited by iodo-acetic acid and iodo-acetamide, both of which attack the Blackman reaction. Since acetamide is without effect, the iodo-acetyl radical must be responsible. The study of the action of the acid is complicated by the fact that its ions penetrate slowly, if at all, so that negative results with this agent are without significance unless penetration can be established. The absorption spectrum of the cells is not affected by concentrations of iodo-acetamide which completely inhibit photosynthesis. This establishes that the chromophore groups of chlorophyll are not involved, and renders it unlikely that any other part of the molecule is. Inasmuch as cyanide likewise inhibits by way of the Blackman reaction, it would seem necessary to postulate that this complex can be attacked at two different loci, which may or may not be on the same molecule.

The presence of the iodo-acetyl radical also gives rise to three other effects. (1) Concentrations (10–5 M or less) too small to inhibit photosynthesis may increase the rate by interacting with the photochemical complex. (2) Concentrations (ca. 10–4 M) which inhibit photosynthesis increase the rate of respiration. (3) Concentrations (10–3 M or more) higher than those required to inhibit photosynthesis inhibit respiration.
THE ESCAPE OF HEMOGLOBIN FROM THE RED CELL DURING HEMOLYSIS
Authors: Ponder Eric , Marsland Douglas
Published: May 2004

By means of measurements from cinematograph films of the time taken for human red cells to lose hemoglobin while hemolyzing, it is shown that small concentrations of saponin bring about a relatively small permeability of the cell membrane to the pigment, whereas large concentrations so destroy the membrane that the theoretical time for loss of pigment through a completely permeable membrane (0.16 second) is very nearly attained. These results are in agreement with those obtained from electrical measurements, and the dependence of permeability on lysin concentration can be explained on the basis of what is known about the rate of transformation of lysin as it reacts with the cell envelope. When cells are hemolyzed by hypotonic solutions, on the other hand, the permeability of the membrane to pigment is nearly constant, irrespective of the tonicity used to bring about lysis.
THE REVERSIBLE HEAT ACTIVATION INDUCING GERMINATION AND INCREASED RESPIRATION IN THE ASCOSPORES OF NEUROSPORA TETRASPERMA
Authors: Goddard David R.
Published: May 2004

The heat activation of Neurospora tetrasperma ascospores is a reversible process, since activated spores may be returned to secondary dormancy by preventing respiration, and these secondarily dormant spores may be induced to germinate by reheating. Activation of the spores brings about a large increase in respiration prior to the germination of the spores. As the spores are reversibly activated or deactivated the rate of respiration is increased or is decreased. By poisoning the cells with iodoacetamide it is possible to prevent all germination without greatly inhibiting this increase in respiration. Precisely with the beginning of germination a secondary rise in respiration occurs. The respiration of the spores is cyanide sensitive. The heat activation has a critical temperature at about 49 to 52°C.; and at a constant temperature within this range, the percentage of the spores activated as plotted against the time, follows an S-shaped population curve.