bluuebunny/crossref_metadata_2025 huggingface dataset:
ON THE PHYSICAL NATURE OF "CYTOTROPISM" AND ALLIED PHENOMENA AND THEIR BEARING ON THE PHYSICS OF ORGANIC FORM
Authors: Rashevsky N.
Published: May 2004

From thermodynamical considerations expressions are derived for the forces which will act on a liquid drop suspended in another liquid, if the latter contains in solution a substance whose concentration is non-uniform. It is shown that forces of attraction and repulsion between two such drops may result, if the drops are seats of chemical reactions, which produce substances diffusing into the surrounding medium.

An estimate of the order of magnitude of such forces is made, and it is found that they may exceed the electrical forces which would result from the charges which the drops may possess.

A possible experimental method of studying such forces is suggested.

The possible connection of the above forces with those observed in the phenomena of "cytotropism," and their bearing on the physical explanation of organic form, especially of the phenomena of "induction," is briefly discussed.
THE EFFECT OF ADDED LOADS UPON THE GEOTROPIC ORIENTATION OF YOUNG GUINEA PIGS
Authors: Upton Morgan
Published: May 2004

It has been found that young guinea pigs when progressing over a surface inclined at an angle α with the horizontal, orient upward in a way such that the path described by an oriented animal is at a mean angle θ with the base of the inclined surface. The magnitude of mean θ increases as the angle of inclination α increases. The function relating θ and α is compound, being made up of two sections with a break which corresponds to a change in the mode of progression of an animal over the surface of the plane.

If a load of constant relative mass is attached to the back of an animal, midway between the fore and hind legs, testing on an inclined surface reveals the fact that the magnitude of mean θ is increased over the entire range of stimulation, with the two values of mean θ (i.e. with and without added load) becoming more nearly equal as they approach 90° as a limiting value. The variation (P.E. of mean θ) is not sensibly changed by attaching a load to an orienting animal; for equal magnitudes of θ, under the two sets of test conditions, the P.E.'s are very nearly equal.
ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. V
Authors: Crozier W. J. , Pincus G.
Published: May 2004

Young rats bearing a mass of 1.06 gm. both at shoulder level on the back and posteriorly at the sacrum exhibit in their geotropic progression a relationship between angle θ of oriented path and inclination α of substratum which differs from those obtained with rats of the same race carrying the same total added load concentrated anteriorly or posteriorly. The distributed load affects more or less equally all the groups of receptor units concerned in tension excitation. It is shown that the variation of orientation is organically determined, quantitatively, by the intensity of tension excitation, regardless of the imposition of the added loads. The bearing of these facts upon the theory of the geotropic orientation is discussed.
ON "REVERSAL" OF PHOTOTROPISM IN PHYCOMYCES
Authors: Castle E. S.
Published: May 2004

Alleged reversal of the phototropism of the sporangiophores of Phycomyces by high intensities of light does not occur if infra-red radiation is properly excluded. Phototropic "indifference" alone occurs at high intensities due to equal photic action on both sides of the sporangiophore. If heat radiation is not screened out, a gradual, negative thermotropic bending takes place.
THE SPECTRAL SENSIBILITY OF THE SUN-FISH AS EVIDENCE FOR A DOUBLE VISUAL SYSTEM
Authors: Grundfest Harry
Published: May 2004

1. An extension of a previously described method makes possible the measurement of the visibility function of Lepomis at high intensities of spectral illumination. This is accomplished by determining the relative energies of various spectral beams which will just produce a visual orienting response by the animal to the movement of a pattern composed of fine lines.

2. The function so determined is different from that obtained with a pattern composed of wide bars and spaces at a lower intensity level.

3. This difference furnishes direct and quantitative proof that the eye of Lepomis is a physiologically duplex visual system and parallels the known anatomical distinctions between the rods and cones.

4. A comparison of the visibility curves of the two systems indicates that both functions are similar in shape but that the cone curve is shifted to the red.

5. It is suggested that this relation between the two systems, which is also found in the human and the fowl, indicates that the photosensory substance is the same in each case for the rods and cones. According to this hypothesis, the shift of the cone curve is due to a common physical cause which depends on differences in the properties of the solvent media in the cones and in the rods.
DISSIMILARITY OF INNER AND OUTER PROTOPLASMIC SURFACES IN VALONIA. III
Authors: Damon E. B.
Published: May 2004

Evidence that the inner and outer protoplasmic surfaces in Valonia are unlike is found in the high P.D. across the protoplasm when the external solution has the same composition as the vacuolar sap. Earlier experiments with artificial sap have been repeated, using natural as well as artificial sap. Good agreement between the data with the natural and the artificial solution was found both in the magnitude of the P.D.'s observed and in the shape of the P.D.-time curves. The P.D.'s, however, were considerably higher than the values formerly reported as usual, while the cells proved much less liable to alteration produced by exposure to sap. It is suggested that the cells used in the recent experiments were in a more vigorous condition, perhaps as a result of exposure to stronger illumination.

The interpretation of the shape of the P.D.-time curves, proposed in an earlier report, and based on the theory of protoplasmic layers, is further discussed. It is assumed that the fluctuations in P.D. are due to an increase in the concentration of K in the main body of the protoplasm.
THE ADSORPTION OF GELATIN BY COLLODION MEMBRANES
Authors: Palmer Albert H.
Published: May 2004

An experimental study has been made of the adsorption of gelatin from solution at 37°C. by collodion membranes. In the case of membranes of high permeability, very high concentrations of gelatin were required to produce maximum adsorption, and the maximum amounts adsorbed were independent of the pH values of the solutions over the range 3.8 to 4.8. With membranes of low permeability, maximum adsorption was reached at lower gelatin concentrations, and the maximum amounts adsorbed varied with the pH, being lower on either side of the isoelectric point, over the range 3.8 to 6.6. The addition of salt in such experiments raised the maximum amount adsorbed to a value equal to that obtained with solutions at the isoelectric point in the absence of salt.

These experiments can be explained by, and seem to lend support to, the theory proposed by Loeb and further developed by Kunitz concerning the effects of pH and salt on the size of gelatin particles in solution.
THE EFFECTS OF CO AND LIGHT ON THE OXYGEN CONSUMPTION AND ON THE PRODUCTION OF CO2 BY GERMINATING SEEDS OF LUPINUS ALBUS
Authors: Tang Pei-Sung
Published: May 2004

The consumption of oxygen by germinating seeds of Lupinus albus can be reversibly inhibited by CO to a maximum extent of 36 per cent with a mixture of 24 per cent O2 and 76 per cent CO at 18°, in darkness. This inhibition is completely abolished when the seed is illuminated. On returning to air, after a period in the CO-O2 mixture, the rate of oxygen consumption is accelerated to as much as 68 per cent over what it had been previously, in air. The production of CO2 is apparently not inhibited by CO. The bearing of these findings on the study of the rates of gas exchange of the seeds as a function of temperature is discussed.
THE KINETICS OF PENETRATION
Authors: Osterhout W. J. V.
Published: May 2004

In a model consisting of a non-aqueous layer (representing the protoplasm) placed between an inner, more acid, aqueous layer (representing the sap) and an outer, more alkaline, aqueous solution (representing the external solution bathing a living cell) the penetration of potassium creates an outwardly directed potential against which potassium continues to diffuse inward, thereby increasing the outward potential. This continues until the steady state is reached. The potassium sets up less potential in entering than in escaping and the net result is an outwardly directed potential. A similar process appears to take place in certain living cells.
ON THE EXCITATION OF TISSUE BY MEANS OF CONDENSER DISCHARGES
Authors: Blair H. A.
Published: May 2004

Equations are derived for the capacity-voltage relations for stimulation of tissue by condenser discharges, using the hypothesis that the local excitatory process p grows under the influence of an applied potential V according to the equation,

See PDF for Equation

where K and k are constants. It is further assumed that the local excitatory process becomes adequate when it attains a value h ± α V where h and α are constants and V is the applied potential at the particular instant that the adequate value is attained. The equations so obtained are applied to the data of several authors on several types of tissue and the agreements obtained are sufficiently good. It is shown in one case that the direct current equation and the condenser discharge equation each derived from the above bases are consistent when applied to data from the same preparation.
CRYSTALLINE TRYPSIN
Authors: Northrop John H.
Published: May 2004

1. If dilute solutions of purified trypsin of low salt concentration at pH from 1 to 7 are heated to 100°C. for 1 to 5 minutes and then cooled to 20°C. there is no loss of activity or formation of denatured protein. If the hot trypsin solution is added directly to cold salt solution, on the other hand, all the protein precipitates and the supernatant solution is inactive.

2. The per cent of the total protein and activity present in the soluble form decreases from 100 per cent to zero as the temperature is raised from 20°C. to 60°C. and increases again from zero to 100 per cent as the solution is cooled from 60°C. to 20°C. The per cent of the total protein present in the soluble (native) form at any one temperature is nearly the same whether the temperature is reached from above or below.

3. If trypsin solutions at pH 7 are heated for increasing lengths of time at various temperatures and analyzed for total activity and total protein nitrogen after cooling, and for soluble activity and soluble (native) protein nitrogen, it is found that the soluble activity and soluble protein nitrogen decrease more and more rapidly as the temperature is raised, in agreement with the usual effects of temperature on the denaturation of protein. The total protein and total activity, on the other hand, decrease more and more rapidly up to about 70°C. but as the temperature is raised above this there is less rapid change in the total protein or total activity and at 92°C. the solutions are much more stable than at 42°C.

4. Casein and peptone are not digested by trypsin at 100°C. but when this digestion mixture is cooled to 35°C. rapid digestion occurs. A solution of trypsin at 100°C. added to peptone solution at zero degree digests the peptone much less rapidly than it does if the trypsin solution is allowed to cool slowly before adding it to the peptone solution.

5. The precipitate of insoluble protein obtained from adding hot trypsin solutions to cold salt solutions contains the S-S groups in free form as is usual for denatured protein.

6. The results show that there is an equilibrium between native and denatured trypsin protein the extent of which is determined by the temperature. Above 60°C. the protein is in the denatured and inactive form and below 20°C. it is in the native and active form. The equilibrium is attained rapidly. The results also show that the formation of denatured protein is proportional to the loss in activity and that the re-formation of native protein is proportional to the recovery of activity of the enzyme. This is strong evidence for the conclusion that the proteolytic activity of the preparation is a property of the native protein molecule.
CRYSTALLINE TRYPSIN
Authors: Northrop John H.
Published: May 2004

The rate of digestion, as determined by the increase in non-protein nitrogen or formol titration, of casein, gelatin, and hemoglobin with crystalline trypsin preparations increases nearly in proportion to the concentration of protein, but with crude pancreatic extract the rate of digestion becomes independent of the protein concentration in concentrations of more than 2.5 per cent. With both enzymes the rate of digestion of mixtures of 5 per cent casein and gelatin is greater than would be expected from the point of view of a compound between enzyme and substrate. The rate of digestion of 5 per cent casein in the presence of 5 per cent gelatin is exactly the same as that of 5 per cent casein alone. This result is obtained with both enzymes. The digestion of casein with crude trypsin follows the course of a monomolecular reaction quite closely while with purified trypsin the velocity constant decreases as the reaction proceeds. In the case of hemoglobin the monomolecular velocity constant decreases with both purified and crude enzyme.

When the reaction is followed by changes in the viscosity of the solution the abnormal effect of changing substrate concentration disappears and the reaction is in fair agreement with the monomolecular equation. The results as a whole indicate that the abnormalities of the reaction are due to the occurrence of several consecutive reactions rather than to the formation of a substrate enzyme compound.
THE COMBINATION OF CERTAIN PROTEINS WITH HYDROCHLORIC ACID
Authors: Hitchcock David I.
Published: May 2004

Electromotive force measurements of cells without liquid junction, of the type Ag, AgCl, HCl + protein, H2, have been made at 30°C. with the proteins gelatin, edestin, and casein in 0.1 M hydrochloric acid. The data are consistent with the assumptions of a constant combining capacity of each protein for hydrogen ion, no combination with chloride ion, and Failey's principle of a linear variation of the logarithm of the mean activity coefficient of the acid with increasing protein concentration. The combining capacities for hydrogen ion so obtained are 13.4 x 10–4 for edestin, 9.6 x 10–4 for gelatin, and 8.0 x 10–4 for casein, in equivalents of combined H+ per gm. of protein.
ON THE RATE OF OXYGEN CONSUMPTION BY FERTILIZED AND UNFERTILIZED EGGS
Authors: Whitaker D. M.
Published: May 2004

1. Unfertilized eggs of Chaetopterus consume about 2.4 mm.3 O2 per hour per 10 mm.3 eggs at 21°C.

2. In the 1st hour after fertilization, the fertilized eggs consume oxygen at about 53 or 54 per cent of this rate, which is about 1.3 mm.3 O2 per hour per 10 mm.3 eggs at 21°C.

3. For the first 6 hours after fertilization, at 21°C., the curve of the rate of oxygen consumption is slightly asymmetrically sigmoid. The prefertilization rate is regained between 4½ and 5 hours after fertilization. Soon after 6 hours, ciliary activity begins, and the rate of oxygen consumption rises rapidly.

4. The unfertilized eggs of Arbacia punctulata consume about 0.36–0.5 mm.3 O2 per hour per 10 mm.3 eggs at 21°C. The absolute determination is difficult as these eggs are highly sensitive to shaking in the manometer vessels, and these difficulties are discussed.

5. The fertilized eggs of Arbacia punctulata consume oxygen at the rate of about 2.0 mm.3 O2 per hour per 10 mm.3 21°C. At 1 hour after fertilization the rate is already rising.

6. A comparison of the absolute rates of oxygen consumption, and the changes in rate at fertilization of these and a number of other eggs, together with a theoretical discussion, and a discussion of discrepancies in measurements on the eggs of Arbacia punctulata, is contained in the fifth paper of this series (21).
OSMOTIC RELATIONSHIPS IN THE HEN'S EGG
Authors: Johlin J. M.
Published: May 2004

Data have been given to illustrate the difficulty of obtaining consistent freezing point data with a viscous fluid such as the yolk of the hen's egg and a technique has been described for obtaining reproducible and accurate results consistently. Further freezing point data have been given which were obtained with both fertile and unfertile hen's eggs by the use of a freezing point method previously described by the writer. These data show that there is a pronounced difference between the freezing points of the yolk and the white in contrast to data obtained by the use of the same method by Howard who found the freezing points of the yolk and the white to be the same.

It was shown by freezing point determinations that even in a mixture of yolk and white osmotic equilibrium is slowly arrived at. This again emphasizes the fact established by Smith and Shepherd that since osmotic equilibrium between yolk and white is slowly arrived at, the postulation of a vital activity at the yolk membrane is unnecessary, since the steady state previously postulated need not be assumed to exist.
THE PROCESS OF PHAGOCYTOSIS
Authors: Mudd Emily B. H. , Mudd Stuart
Published: May 2004

The phagocyte, then, is a complex system delicately responsive to internal and external influences. Interfacial tensions, and under certain conditions viscosity, are critical factors in determining the ingestion of particles with which the phagocyte has come into contact. Deductions from the formulation of these factors by Fenn and Ponder are in agreement with observation and with experimental analysis. However, other and still unformulated forces also enter into the behavior of these remarkable cells.
THE CHARACTERISTICS OF ULTRAFILTRATES OF PLASMA
Authors: Ingraham Raymond C. , Lombard Charles , Visscher Maurice B.
Published: May 2004

1. Calculations from the Fick diffusion law are shown to predict that membrane equilibria should be established during the course of ultrafiltration.

2. It is shown that the chloride ion is more concentrated and the sodium ion less concentrated in the ultrafiltrate than in the plasma from which the ultrafiltrate was derived.

3. It has been found that by increasing the base bound by protein through a reduction in the bicarbonate content the difference between the plasma concentration and the ultrafiltrate concentration for the several ions studied increases.

4. Calculations from the Donnan equation as to the magnitude of the change in base bound by protein at differing hydrogen ion concentrations are in substantial agreement with the observed values, thus rendering it probable that the membrane equilibrium effect is responsible for the change in distribution ratios observed.

5. It is pointed out that the observed difference in the distribution ratio of cations from that of the chloride anion is probably to be explained by the influence of protein in lowering the activity coefficient of cations when on the alkaline side of the isoelectric point.

6. It is pointed out that account must be taken of these observations in any consideration of the rôle of ultrafiltration in the production of any secretion or body fluid.
THE EFFECT OF CYANIDE AND OF VARIATION IN ALKALINITY ON THE OXIDATION-REDUCTION POTENTIAL OF THE HEMOGLOBIN-METHEMOGLOBIN SYSTEM
Authors: Barnard Robert D.
Published: May 2004

The potentiometric method was applied to the study of the influence of cyanide and of hydroxyl ion on methemoglobin. Both of these ions appear to combine with the iron of the methemoglobin molecule and reduce its oxidant activity. From the magnitude of the effect produced by cyanide and by variation in pH on the oxidation-reduction potential of the methemoglobin-hemoglobin system, it is concluded that cyanmethemoglobin and alkaline methemoglobin are undissociated ferric compounds, the first with cyanide and the second with hydroxyl.

Electronic formulas, based on the electrical properties of the hemoglobin derivatives, are suggested.
ELECTRICAL RESPONSES FROM THE LATERAL-LINE NERVES OF CATFISH. I
Authors: Hoagland Hudson
Published: May 2004

1. Records of impulses from the lateral-line nerves of catfish show that the lateral-line organs are in a state of continuous activity, producing a massive discharge of impulses.

2. The discharge may be increased during the direct application of pressure on the skin over the lateral-line canal, by ripples in the water, by irregular currents of water, and by movements of the fish's trunk.

3. The asynchronously discharging lateral-line organs respond to vibratory stimuli from tuning-forks by getting into phase with each other and by beating synchronously at frequencies ranging from 20 to 70 per second. The frequency of beating for a given preparation is independent of the frequency of the tuning-fork for the fork frequencies of 100, 200, and 250 double vibrations which were used.

4. The continuous discharge of the lateral-line system is markedly changed by alteration of temperature. The frequency declines on lowering the temperature and rises on increasing it. Spinal and facial nerves in the catfish fail to yield nerve impulses in response to changes of the skin temperature between 0° and 28°C., although the intact animal is known to be sensitive to temperature differences.

5. The action of the lateral-line system of Ameiurus in inhibiting responses initiated through the skin and ears (Parker and Van Heusen, 1917) is discussed in the light of the present experiments.
DEVELOPMENT OF THE EGG OF THE MACKEREL AT DIFFERENT CONSTANT TEMPERATURES
Authors: Worley Leonard G.
Published: May 2004

1. Mackerel egg development was followed to hatching at constant temperatures of 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, and 24°C. Experiment showed that typical development could be realized only between 11° and 21°.

2. The length of the developmental period increases from 49.5 hours to 207 hours when the temperature is lowered from 21° to 10°C.

3. The calculated µ for the development of the mackerel egg is about 19,000 at temperatures above 15° and approximately 24,900 for temperatures below 15°C. 15° is, apparently, a critical temperature for this process.

4. The calculated values of µ for eight stages of development preceding hatching, i.e. 6 somites, 12 somites, 18 somites, 24 somites, three-quarters circles, four-fifths circles, five-sixths circles, and full circles, are essentially the same as the µ's for hatching, indicating that the rate of differentiation up to hatching is governed by one process throughout. Critical temperatures for these stages approximate 15°.

5. The total mortality during the incubation period was least at 16°C. where it amounted to 43 per cent. At temperatures above and below this there was a steady increase in the percentage of mortality which reached 100 per cent at 10° and 21°.
PHOTIC STIMULATION AND LEG MOVEMENTS IN THE CRAYFISH
Authors: Kropp B. , Enzmann E. V.
Published: May 2004

When Cambarus clarkii is exposed to a source of light so that both eyes are equally illuminated, leg movements of the two sides are equal in frequency and amplitude.

On covering one eye and exposing the uncovered eye to light, leg movements on the side of the uncovered eye are more frequent and are of greater amplitude than on the side of the covered eye. On covering the exposed eye also the leg movements on the two sides again tend to become equal in frequency and amplitude.

When one eye is lost and the other remains functional, the leg movements on the side of the lost eye will be similar to those on the side of a normal, covered eye.
THE MODIFICATION OF ANTIBODIES BY FORMALDEHYDE
Authors: Mudd Stuart , Joffe Eleanore W.
Published: May 2004

Certain strains of bacteria which have only minimal zeta potentials over a wide range of pH, and upon which surface deposits can be formed, afford a favorable means of studying certain chemical and physical properties of the surface deposits.

Films of specific antibody-globulin upon these bacteria possess basic groups which can combine with formaldehyde. Combination of these groups with HCHO under the conditions of the present experiments shifts the isoelectric point of the sensitizing film toward the acid side by about 0.6 to 0.8 pH unit, and reduces the agglutinating tendency of the sensitizing film.

Antibodies may be formalinized before combination with antigen without marked change in their specific combining affinities. The properties of the sensitizing films are similar whether formol treatment occurs before or after the antigen-antibody combination.

The nature of the basic groups has been discussed.
THE COUPLED REDOX POTENTIAL OF THE LACTATE-ENZYME-PYRUVATE SYSTEM
Authors: Baumberger J. Percy , Jürgensen J. J. , Bardwell Kathleen
Published: May 2004

1. The term "coupled redox potential" is defined.

2. The system lactic ion

See PDF for Equation

pyruvic ion + 2H+ + 2e is shown

to be reversible (when the enzyme is lactic acid dehydrogenase) and its coupled redox potential between pH 5.2 and 7.2 at 32°C. is:

See PDF for Equation

3. The free energy of the reaction:

lactic ion (1m) → pyruvic ion (1m) = -ΔF = –14,572.

4. The standard free energy of formation (ΔF298) of pyruvic acid (l) is estimated at –108,127. This is merely an approximation as some necessary data are lacking.

5. The importance of coupled redox potentials as a factor in the regulation of the equilibrium of metabolites is indicated.
GELATINASE AND THE GATES-GILMAN-COWGILL METHOD OF PEPSIN ESTIMATION
Authors: Smith Elizabeth R. B.
Published: May 2004

The Gates photographic film method for pepsin estimation as developed by Gilman and Cowgill measures an activity corresponding to that determined by the hemoglobin method of Anson and Mirsky rather than that resulting from the use of the gelatin viscosity technique. Therefore, the presence of gelatinase is not a source of great error in the gelatin film procedure.
CRITICAL FREQUENCY OF FLICKER AS A FUNCTION OF INTENSITY OF ILLUMINATION FOR THE EYE OF THE BEE
Authors: Wolf Ernst
Published: May 2004

The bee's characteristic response to a movement of its visual field is used for the study of the relation between critical frequency of flicker and illumination. The critical flicker frequency varies with illumination in such a way that with increasing flicker frequency the intensity of illumination must be increased to produce a threshold response in the bee.

The illuminations required to give a response in a bee at different flicker frequencies closely correspond to the intensities for threshold response in visual acuity tests. This is due to the different thresholds of excitability of the elements of the ommatidial mosaic.

An analysis of the variation of the values for threshold intensities at the several flicker frequencies shows that the variation depends upon flicker frequency and upon the number of elements functioning at different intensities.
THE EFFECT OF ULTRAVIOLET LIGHT ON PHOTOSYNTHESIS
Authors: Arnold William
Published: May 2004

1. An unidentified unit in the mechanism of the photosynthesis of Chlorella pyrenoidosa is rendered inactive by the absorption of one quantum of ultraviolet light (2537 Å wave length).

2. The same irradiation has no effect on the normal respiration of Chlorella pyrenoidosa. Experiments have not yet been made on the respiration inhibitable by HCN.

3. No chemical change was detected in the chlorophyll extracted from irradiated cells.
THE ORDER OF THE BLACKMAN REACTION IN PHOTOSYNTHESIS
Authors: Arnold William
Published: May 2004

On the assumption that photosynthesis is a cyclic process and that irradiation by ultraviolet light does not change the reaction constants, the Blackman reaction is shown to be of first order.
THE ESTIMATION OF TRYPSIN WITH HEMOGLOBIN
Authors: Anson M. L. , Mirsky A. E.
Published: May 2004

The formation from hemoglobin of split products not precipitable by trichloracetic acid is taken as a measure of tryptic activity. The split products are estimated colorimetrically.

Many measurements of tryptic activity can be made in a short time and different samples of hemoglobin yield the same results.
INTERMITTENT STIMULATION BY LIGHT
Authors: Hecht Selig , Verrijp Cornelis D.
Published: May 2004

A theoretical treatment of the data of intermittent stimulation by light is presented in terms of the familiar reversible photochemical system previously used for other properties of vision. It appears that such a system considered merely as the initial event in photoreception is capable of giving a first order quantitative description of the relation between critical frequency and illumination for different retinal regions, and of Talbot's law. Moreover the development of this concept shows that the general form of most of the existing relationships in flicker are already apparent in the characteristics of the behavior of this initial photochemical event.
THE CONVERSION OF FAT TO CARBOHYDRATE IN THE GERMINATING CASTOR BEAN
Authors: Daggs Ray G. , Halcro-Wardlaw H. S.
Published: May 2004

The combustion respiratory quotients of castor beans germinated to various stages, depending upon the length of the hypocotyl, were determined by means of a modified oxycalorimeter.

After germination was well started, the respiratory quotient of the combusted germinated seed increased as the stage of germination increased, indicating a change from an oxygen-poor to an oxygen-rich substance, probably fat to sugar.

The accuracy of the method was checked by organic combustions.

The seat of formation of the oxygen-rich substance is in the endosperm.
BACTERIAL CELL METABOLISM UNDER ANAEROBIC CONDITIONS
Authors: Walker H. H. , Winslow C.-E. A. , Mooney M. Grace
Published: May 2004

Escherichia coli has been cultivated in a peptone water medium saturated continuously with nitrogen by use of a gas train so as to produce anaerobic conditions. Under these circumstances growth was greatly inhibited. Cultures which originally contained 11 million bacteria per cc. showed on the average only 32 million after 5 hours (as compared with 655 million in similar cultures saturated with air).

The metabolic activity of the cells in such a culture was greatly reduced by the anaerobic conditions. It actually fell off from 42 mg. x 10–11 per cell per hour during the 1st hour to 27 mg. during the 2nd hour and rose only to a maximum of 68 during the 3rd hour. Similar cultures saturated with air showed a rise from 37 mg. x 10–11 during the 1st hour to 123 during the 2nd hour.

The addition of glucose to the medium, under aerobic conditions, has been shown in previous studies to cause only a slight increase in bacterial numbers (861 instead of 655 million after the 5th hour). In the cultures aerated with nitrogen, the addition of glucose has no effect during the first hours. There is again a long lag period and a reduced metabolic rate. After the 2nd hour, however, a wholly different phenomenon manifests itself. The bacterial population increases more rapidly than in the anaerobic peptone medium (reaching a maximum of 142 million after 5 hours). This growth is accompanied by an enormous increase in the rate of CO2 yield, which reaches 211 mg. x 10–11 per cell per hour during the 4th hour (nearly double the maximum values recorded under aerobic conditions). The same phenomenon is, of course, illustrated by the enormous yield of CO2 produced by the action of fermenting organisms in carbohydrate media recorded by Anderson (1924) and other students of the obligate anaerobes. We have here, however, a somewhat striking illustration of the distinct type of metabolic activity manifested by a facultative organism under anaerobic conditions in the presence of sugar measured on a cell-per-hour basis. This is a quantitative illustration of the "life without air" described by Pasteur.
A PHOTOELECTRIC DENSITOMETER FOR USE WITH SUSPENSIONS
Authors: Stier T. J. B. , Arnold W. , Stannard J. N.
Published: May 2004

A device for quickly and accurately measuring the population density of a suspension of microorganisms, permitting the preparation of yeast suspensions of known density to within 1 per cent error, was constructed with two Visitron photoelectric cells, a single light of high intensity and a good Wheatstone bridge for balancing the currents from the two photoelectric cells. A large Pyrex milk culture tube holding the suspension is placed in the path of one beam of light coming through a small longitudinal slit and thence to one photocell; a second similar slit directs another beam of light upon the second photocell, thus causing dissimilar currents to flow, the ratio of whose magnitudes may be measured by the bridge resistances. A relation between these currents and the relative light intensities is shown, and the one significant unmeasurable variable (the characteristic constant of a photocell) is practically eliminated by the use of a method of ratios.

After careful standardization of technique the apparatus proved more accurate than other methods available for the purpose indicated. In rapid use its accuracy may be put safely at 1 per cent for measuring the densities of cultures of approximately the same age and composed of cells having comparable optical characteristics.
THE REVERSIBLE INACTIVATION OF BACTERIOPHAGE BY BICHLORIDE OF MERCURY
Authors: Krueger A. P. , Baldwin D. M.
Published: May 2004

1. The complete inactivation of antistaphylococcal phage by HgCl2 (2.8 per cent for 216 hours) can be reversed by precipitation of Hg++ with restoration of the phage to its original titre.

2. This behavior seems more compatible with the known properties of certain enzymes than with those of living protoplasm.
THE KINETICS OF PENETRATION
Authors: Osterhout W. J. V. , Kamerling S. E.
Published: May 2004

A model is described which throws light on the mechanism of accumulation. In the model used an external aqueous phase A is separated by a non-aqueous phase B (representing the protoplasm) from the artificial sap in C. A contains KOH and C contains HCl: they tend to mix by passing through the non-aqueous layer but much more KOH moves so that most of the KCl is formed in C, where the concentration of potassium becomes much greater than in A. This accumulation is only temporary for as the system approaches equilibrium the composition of A approaches identity with that of C, since all the substances present can pass through the non-aqueous layer. Such an approach to equilibrium may be compared to the death of the cell as the result of which accumulation disappears.

During the earlier stages of the experiment potassium tends to go in as KOH and at the same time to go out as KCl. These opposing tendencies do not balance until the concentration of potassium inside becomes much greater than outside (hence potassium accumulates). The reason is that KCl, although its driving force be great, moves very slowly in B because its partition coefficient is low and in consequence its concentration gradient in B is small. This illustrates the importance of partition coefficients for penetration in models and in living cells. It also indicates that accumulation depends on the fact that permeability is greater for the ingoing compound of the accumulating substance than for the outgoing compound.

Other things being equal, accumulation is increased by maintaining a low pH in C. Hence we may infer that anything which checks the production of acid in the living cell may be expected to check accumulation and growth.

This model recalls the situation in Valonia and in most living cells where potassium accumulates as KCl, perhaps because it enters as KOH and forms KA in the sap (where A is an organic anion). In some plants potassium accumulates as KA but when HCl exists in the external solution it will tend to enter and displace the weaker acid HA (if this be carbonic it can readily escape): hence potassium may accumulate to a greater or less extent as KCl.

Injury of the cell may produce a twofold effect, (1) increase of permeability, (2) lessened accumulation. The total amount of electrolyte taken up in a given time will be influenced by these factors and may be greater than normal in the injured cell or less, depending somewhat on the length of the interval of time chosen.
ON GUAIACOL SOLUTIONS
Authors: Shedlovsky Theodore , Uhlig Herbert H.
Published: May 2004

1. Measurements on the densities, viscosities, dielectric constants, and specific conductances of pure anhydrous and water-saturated guaiacol at 25°C. are reported.

2. The solubility of water in guaiacol at 25°C., and its effect on the electrical conductivity of a sodium guaiacolate solution is given.

3. Electrical conductivity measurements are reported on solutions of sodium and potassium guaiacolates in water-saturated guaiacol at 25°C.

4. The decrease of electrical conductivity with increasing concentration for these salts is explained on the basis of an ionic equilibrium combined with the interionic attraction theory of Debye and Hückel.

5. The limiting equivalent conductances of sodium and potassium guaiacolates in water-saturated guaiacol at 25°C., the corresponding limiting ionic mobilities, and the dissociation constants are computed from the conductivity measurements. The salts are found to be weak electrolytes with dissociation constants of the order of 5 x 10–6.
INFLUENCE OF DEATH CRITERIA ON THE X-RAY SURVIVAL CURVES OF THE FUNGUS, NEUROSPORA
Authors: Uber Fred M. , Goddard David R.
Published: May 2004

1. When ascospores of Neurospora tetrasperma were irradiated with 11 kv. X-rays, the single spore cultures obtained displayed a wide variety of mutated forms.

2. Control germinations of ascospores showed uniform behavior, ranging from 92–95 per cent germination.

3. The shape of the survival curves was found to be a function of the criterion of death. The following criteria were used: germination, growth, production of mature ascospores, and the production of normal perithecia.

4. The germination survival curve exhibited a rhythmic variation with dosage. Germination is not a significant criterion of death.

5. Half-survival dosages for growth and ascospore production were approximately 30,000 and 20,000 roentgens, respectively.

6. Multiple hit-to-kill relations were found on the basis of the quantum hit theory; no accurate analysis was possible.

7. The studies indicate that ascospore death does not result from a single well defined reaction, but rather from the integrated effects of several deleterious processes initiated by the radiation.
ON NORRIS' THEORY FOR THE SHAPE OF THE MAMMALIAN ERYTHROCYTE
Authors: Ponder Eric
Published: May 2004

This paper is concerned with an attempt to put Norris' theory for the shape of the mammalian erythrocyte into a quantitative form. The theory supposes that the biconcave form of the cell is brought about by an expansive force enlarging the surface, and is also supposed to apply to the formation of the myelin forms of lecithn. The attempt is not successful, and is published merely because it is suggestive. Various points regarding the shape of the cell, the curvature of its surface, and the kind of system to which Norris' theory might be supposed to apply, are discussed, and an empirical formula is given for the curve which bounds the cross-section of the cell. This empirical formula describes the shape almost to perfection.
THE PHOTOTROPIC EFFECT OF POLARIZED LIGHT
Authors: Castle E. S.
Published: May 2004

For the growing cell of Phycomyces, a difference in the phototropic effect of light is described depending on its plane of polarization with reference to the axis of the cell. The difference which is found is primarily due to differences in the reflection losses at the cell surface. The magnitude of the effect approximates that deduced from the theory of phototropism suggested for this system. No specific effect of plane polarized light on the growth processes of the cell need be postulated.
BOUND WATER IN MUSCLE
Authors: Brooks J.
Published: May 2004

1. The amount of free unfrozen water, i.e. water acting as normal solvent, in frog's muscle at temperatures below the initial freezing-point has been calculated from the vapour pressure isotherm of the muscle.

2. Significant amounts of free water are present at –20°C. The total amount of unfrozen water at –20°C. cannot, therefore, be taken as a measure of the bound water in muscle.

3. The calculated values of free water, when compared with experimentally determined values of total unfrozen water, indicate that the amount of bound water in muscle at various temperatures is small.

4. A temperature considerably below –20°C., roughly between –40° and –60°C., is required to freeze completely the free water in muscle.
THE INFLUENCE OF MINIMAL NARCOTIC DOSES ON THE RESPIRATION OF ERYTHROCYTES
Authors: Fleischmann Walter , Rand Charles S.
Published: May 2004

Low concentrations of ethyl alcohol stimulate the respiration of mammalian erythrocytes in vitro.

Low concentrations of ethyl urethan remain without effect on, or tend slightly towards depressing the respiration of mammalian erythrocytes in vitro.

It is suggested that this may be due to the oxidizable nature of alcohol, and the non-oxidizable nature of urethan, properties which come into evidence only when these narcotics are present in such low concentrations that the threshold of inhibition (narcosis) has not been reached.
THE ULTRAVIOLET ABSORPTION SPECTRUM OF PEPSIN
Authors: Gates Frederick L.
Published: May 2004

The ultraviolet absorption spectrum of Northrop's pure crystalline pepsin has been determined. The curve of calculated molecular extinction coefficients is given. There is noted a general resemblance of the absorption curve for pepsin to that for urease and tyrosine; the absorption band is maximum at 2750–2800 Å.µ., minimum near 2500. A slight hump on either side of the peak of the extinction curve may be significant.
SEARCH FOR MITOGENETIC RADIATION BY MEANS OF THE PHOTOELECTRIC METHOD
Authors: Lorenz Egon
Published: May 2004

The intensity of mitogenetic radiation was estimated from data given by Gurwitsch.

The sensitivity of the biological method and of the physical methods were compared.

With onion-base pulp and onion roots as mitogenetic inductors, the photographic method gave no perceptible blackening for exposures up to 184 hours.

A photoelectric counter tube was described with cadmium as photoelectric metal. Its sensitivity was such that a radiation intensity of 10 to 15 quanta per cm.2 per second of the Hg line 2536 A was detectable.

Spurious effects produced by the counter tube were described and means for their avoidance given.

A number of different biological materials, all supposed to be excellent mitogenetic radiators, were investigated by means of the counter tube. No mitogenetic radiation could be detected.
THE PREPARATION OF THE GRADED COLLODION MEMBRANES OF ELFORD AND THEIR USE IN THE STUDY OF FILTERABLE VIRUSES
Authors: Bauer Johannes H. , Hughes Thomas P.
Published: May 2004

1. The method described by Elford for the preparation of graded collodion membranes suitable for ultrafiltration was found to give excellent results, and his findings are fully confirmed.

2. A formula is given for the preparation of collodion from which satisfactory membranes of graded porosity can be prepared.

3. The technique and apparatus used in the preparation, and standardization of membranes are described in detail.

4. The technique and apparatus required for ultrafiltration experiments are described, and some drawbacks encountered in the experiments are discussed.

5. The results of ultrafiltration experiments show that the pores of the membranes are remarkably uniform in size.
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Osterhout W. J. V.
Published: May 2004

The outstanding features of the action curve in Nitella are explained as due to the movement of potassium ions accompanied by increase of permeability. This may be useful as a working hypothesis since it accounts not only for the normal behavior but also for many striking deviations which will be treated in subsequent papers.

The views here set forth are in harmony with the local circuit theory of stimulation.
THE KINETICS OF PENETRATION
Authors: Kamerling S. E. , Osterhout W. J. V.
Published: May 2004

To imitate cells which have ceased to grow we have made models in which artificial sap is separated from the external solution by a non-aqueous layer (representing the protoplasm). A stream of CO2 is bubbled through the artificial sap to imitate its production by the living cell.

Potassium passes from the external solution through the non-aqueous layer into the artificial sap and there reacts with CO2 to form KHCO3: its rate of entrance depends on the supply of CO2. Hence the increase of volume depends on the supply of CO2 (as is probably true of the living cell).

By regulating the supply of CO2 and the osmotic pressure we are able to keep the volume and composition of the artificial sap approximately constant while maintaining a higher concentration of potassium than in the external solution. In these respects the model resembles certain mature cells which have ceased to grow.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G.
Published: May 2004

The inorganic constituents of the sap of Rheum (rhubarb), Rumex (field sorrel), and Oxalis (wood sorrel) show a great preponderance of cations over anions, as would be expected if the cations entered chiefly as hydrates (other possibilities will be discussed in Part 2).
SOME TEMPERATURE CHARACTERISTICS IN MAN
Authors: Hoagland Hudson , Perkins Clifton T.
Published: May 2004

The value of µ = 29,400 has been found for the human heart beat over the temperature range of approximately 4.7°C. This value is different from that of 24,000 calories which has been obtained for the effect of temperature on judgments of short durations.

The evidence indicates that the estimation of short time intervals is controlled by a chemical master reaction which is independent of the pulse rhythm.
FREEZING POINTS OF ANTI-COAGULANT SALT SOLUTIONS
Authors: Hitchcock David I. , Dougan Ruth B.
Published: May 2004

By a method involving equilibration of ice and solution, and analysis of the solution, freezing point depressions of solutions of sodium citrate, oxalate, and fluoride have been determined over the range Δ = 0.45 to 0.65°C. Determinations with sodium chloride solutions have confirmed the accuracy of the method. In each case the freezing point depression is given, within 0.002°C., as a linear function of the concentration. By the use of these linear equations it is possible to prepare a solution of any of these four salts isotonic with a given biological fluid of known freezing point, provided the latter falls within the range studied.