bluuebunny/crossref_metadata_2025 huggingface dataset:
SPECTROPHOTOMETRIC STUDIES OF PENETRATION
Authors: Irwin Marian
Published: May 2004

The rate of diffusion through the non-aqueous layer of the protoplasm depends largely on the partition coefficients mentioned above. Since these cannot be determined we have employed an artificial system in which chloroform is used in place of the non-aqueous layer of the protoplasm. The partition coefficients may be roughly determined by shaking up the aqueous solutions with chloroform and analyzing with the spectrophotometer (which is necessary with methylene blue because we are dealing with mixtures). This will show what dyes may be expected to pass through the protoplasm into the vacuole in case it behaves like the artificial system.

From these results we may conclude that the artificial system and the living cell act almost alike toward methylene blue and azure B, which supports the notion of non-aqueous layers in the protoplasm.

There is a close resemblance between Valonia and the artificial system in their behavior toward these dyes at pH 9.5.

In the case of Nitella, on the other hand, with methylene blue solution at pH 9.2 the sap in the artificial system takes up relatively more azure B (absorption maximum at 650 mµ) than the vacuole of the living cell (655 mµ). But both take up azure B much more rapidly than methylene blue.

A comparison cannot be made between the behavior of the artificial system and that of the living cell at pH 5.5 since in the latter case there arises a question of injury to cells before enough dye is collected in the sap for analysis.
PHYSIOLOGICAL ONTOGENY
Authors: Cohn A. E. , Mirsky A. E. ,   With the Assistance of Yetta Porosowsky.
Published: May 2004

We have studied by means of glass electrodes the hydrogen ion concentration of the blood of chicken embryos from 8 to 20 days. When plotted as a curve, the average data show that a constant change takes place in the measurement, being acid at the beginning of this period and becoming alkaline toward its end. The acid reaction we think was characteristic not only of the embryos of fowl, but of the fetuses of cats and indeed as Warburg has shown of rapidly growing tissue in general. We have suggested the possibility, though we have no data to substantiate the suggestion, that the hydrogen ion concentration may under conditions like these, seeing that the curve of change resembles that of oxygen consumption, be expressive of changes in the rate of metabolism.
THE COMBINATION OF GELATIN WITH HYDROCHLORIC ACID
Authors: Hitchcock David I.
Published: May 2004

1. Cooper's gelatin purified according to Northrop and Kunitz exhibited a minimum of osmotic pressure and a maximum of opacity at pH 5.05 ±0.05. The pH of solutions of this gelatin in water was also close to this value. It is inferred that such gelatin is isoelectric at this pH and not at pH 4.70.

2. Hydrogen electrode measurements with KCl-agar junctions were made with concentrated solutions of this gelatin in HCl up to 0.1 M. The combination curve calculated from these data is quite exactly horizontal between pH 2 and 1, indicating that 1 gm. of this gelatin can combine with a maximum of 9.35 x 10–4 equivalents of H+.

3. Conductivity titrations of this gelatin with HCl gave an endpoint at 9.41 (±0.05) x 10–4 equivalents of HCl per gram gelatin.

4. E.M.F. measurements of the cell without liquid junction, Ag, AgCl, HCl + gelatin, H2, lead to the conclusion that this gelatin in 0.1 M HCl combines with a maximum of 9.4 x 10–4 equivalents of H+ and 1.7 x 10–4 equivalents of Cl- per gram gelatin.
SALT ERROR OF INDICATORS DUE TO STANDARD ALKALINE BUFFERS THEMSELVES. II
Authors: McBain J. W. , Laing M. E. , Clark O. E.
Published: May 2004

Previous results of the comparison of colors given by indicators in alkaline buffers and pure aqueous sodium hydroxide have been repeated and confirmed. The electrometric determinations show that the sodium hydroxide was pure and gave theoretical values for the concentration of hydroxyl ion. The slight but distinct neutralising effect of dilute solutions of alkali has been measured electrometrically and the allowances to be made are recorded graphically. It is found that whereas alizarin yellow G, tropæolin O and thymol violet may be used without appreciable error (in accordance with our previous communication) the grave discrepancies remain for phenolphthalein, o-cresol phthalein and thymol blue and phenol red which must be ascribed to salt error in the alkaline buffer itself.
PROTEIN COAGULATION AND ITS REVERSAL
Authors: Mirsky A. E. , Anson M. L.
Published: May 2004

1. The preparation from completely coagulated hemoglobin of crystalline soluble hemoglobin is described.

2. This soluble hemoglobin by all the tests tried has been indistinguishable from normal native hemoglobin which has never been coagulated.

3. The coagulation of hemoglobin is probably reversible.

4. Since hemoglobin is a typical coagulable protein, protein coagulation in general is probably reversible.
PROTOPLASMIC POTENTIALS IN HALICYSTIS
Authors: Blinks L. R.
Published: May 2004

The cells of Halicystis impaled on capillaries reach a steady P.D. of 60 to 80 millivolts across the protoplasm from sap to sea water. The outer surface of the protoplasm is positive in the electrometer to the inner surface. The P.D. is reduced by contact with sap and balanced NaCl-CaCl2 mixtures; it is abolished completely in solutions of NaCl, CaCl2, KCl, MgSO4, and MgCl2. There is prompt recovery of P.D. in sea water after these exposures.
OSMOSIS OF LIQUIDS. III
Authors: Schreinemakers F. A. H.
Published: May 2004

If only one substance S passes through a membrane, the nature of this membrane is not of importance with respect to the direction of the diffusion; this is namely determined only by the O.S.A. of the two liquids.

If, however, more substances pass through a membrane, the nature of this membrane is of great importance.

If n substances diffuse through a membrane, we can distinguish 2n cases, when we take into consideration only the direction in which each of these substances passes through the membrane; if we call each of these cases a D.T. (diffusion-type), 2n D.T.'s may be conceived. Now we can deduce: one of these D.T.'s is not possible, the other 2n x 1 D.T.'s are thermodynamically admissible. The composition of the two liquids determines which of the D.T.'s is not possible; the nature of the membrane determines which of the 2n x 1 other D.T.'s will occur.
SOLUBILITY CURVES OF MIXTURES AND SOLID SOLUTIONS
Authors: Northrop John H. , Kunitz M.
Published: May 2004

It is shown that the relative amounts and the solubilities of the two components of a mixture or solid solution may be calculated from the solubility curve of the mixture or the solid solution.
THE SORPTION OF BACTERIOPHAGE BY LIVING AND DEAD SUSCEPTIBLE BACTERIA
Authors: Krueger Albert P.
Published: May 2004

The above data relating to the antistaphylococcus phage and single strain of S. aureus with which previous papers have been concerned (9, 10, 11, 12), bring out the following points.

(a) For live, resting, susceptible B suspended in broth as well as for B in a P-B mixture during the logarithmic phases of B growth and P formation, P is distributed in a manner typical of numerous materials soluble in both phases of a two phase system, i.e., distribution proceeds in accordance with the equation Cb/Ca = K where Cb = extracellular P/ml. of broth and Ca = intracellular P/ml. of B. The combination is quantitatively reversible.

(b) With heat-killed, susceptible B, P distribution is of the adsorptive type, expressible in the form of the adsorption isotherm equation a = kC1/n. The average value of 1/n is 0.80 in agreement with the results of von Angerer (2). Under ordinary conditions dead B take up much more P than do live B, the reaction proceeding to > 99 per cent completion. The combination of P with dead B is not demonstrably reversible and with high initial P/B ratios saturation of B with P is effected. Bacteria killed at 65°C., 80°C. and 100°C. show no differences in adsorptive ability.

(c) The rates at which live, resting, susceptible B and heat-killed, susceptible B remove P from solution do not differ significantly. Velocity constants of the process calculated from

See PDF for Equation

agree satisfactorily. It is shown that the time interval consumed is concerned with an actual reaction between P and B and not with diffusion of P through the broth to B.

(d) P determinations have been found to serve as satisfactory indicators for B growth in P-B mixtures where [B] is to be maintained at a constant level. Very small increments in [B] give rise to measurable increases in P by virtue of the fact that dP/dt is proportional to a power of the rate dB/dt (9).

(e) Similarly [P] estimations will detect death of B cells in P-live B suspensions. Dead B take up large amounts of P irreversibly; such P cannot function in the titration and the result is a sharp drop in [P] of controls.
SALT EFFECTS ON SWARMERS OF DUNALIELLA VIRIDIS TEOD
Authors: Baas-Becking L. G. M.
Published: May 2004

1. Dunaliella viridis Teodoresco thrives equally well in solutions of NaCl 1 to 4 mol and pH 6 to 9.

2. The organism is sensitive to calcium and magnesium, especially in acid medium.

3. Calcium and magnesium are antagonistic. In a molar solution of NaCl the antagonistic relation Mg:Ca is 4 to 5. In a 4 molar solution of NaCl the proportion becomes many times as great (20:1).

4. Although the strains used in this investigation did not occur in sea water concentrates, the increase in the antagonistic ratio Mg:Ca in which they can live closely paralleled the changes in this ratio which take place when sea water evaporates.

5. The other organisms which occurred in the cultures each show a specific relation to Ca and Mg.

6. The size of the cells of Dunaliella does not decrease with increasing NaCl content.
GEOTROPIC EXCITATION IN HELIX
Authors: Hoagland H. , Crozier W. J.
Published: May 2004

Rotation of an inclined surface on which Helix is creeping straight upward, such that the axis of the animal is turned at a right angle to its previous position, but in the same plane, leads to negatively geotropic orientation after a measurable latent period or reaction time. The duration of the latent period is a function of the slope of the surface. The magnitude of the standard deviation of the mean latent period is directly proportional to the mean latent period itself, so that the relative variability of response is constant. The dependence of reaction time upon extent of displacement from symmetrical orientation in the gravitational field is found also by tilting the supporting surface, without rotation in the animal's own plane. On slopes up to 55°, the relation between latent period and the sine of the slope is hyperbolic; above this inclination, the latent period sharply declines. This change in the curve is not affected by the attachment of moderate loads to the snail's shell (up to 1/3 of its own mass), and is probably a consequence of loss of passive stable equilibrium when rotated. When added loads do not too greatly extend the snail's anterior musculature, the latent period for the geotropic reaction is decreased, and, proportionately, its σ. These facts are discussed from the standpoint that geotropic excitation in these gasteropods is due to impressed muscle-tensions.
A CHEMICAL EXPLANATION OF THE VARIABILITY OF THE GROWTH RATE
Authors: Rahn Otto
Published: May 2004

The general belief that uniform cells under uniform conditions will all multiply at the same moment implies that the smallest units of the chromosomes, i.e., either the genes or the molecules of which the genes are composed, all double at exactly the same moment in all cells.

Since the doubling of chromosomes is a synthetic chemical process, it seems more probable that it would follow chemical laws. With the assumption that the corresponding molecules in a number of uniform cells obey the mass law in their process of doubling, a definite order in the multiplication of identical cells is established which can be formulated mathematically for the simplest case. This is the same assumption which the author has used to account for the differences in the order of death between bacteria and higher organisms.

This theory demands a great variability of the growth rate of uniform cells, so great that it must be experimentally measurable even for cells with a million molecules to the chromosome.

The theory demands further that the frequency curve of cell divisions plotted for successive time intervals, be skewed to the left, and that the relative range of variation become smaller as the number of genes or gene-type molecules increases.

Experiments on the growth rate of Bacterium aerogenes and Saccharomyces ellipsoideus showed regularly a frequency curve skewed to the left. The yeast had a relatively narrower range of variability than the bacterium.

Even with multicellular organisms, theoretical calculations show a range of variation of the growth rate from the egg cell which should still be measurable though it decreases relatively with the number of cells produced. An experiment on the size of bacteria colonies at different ages of development agreed with the theory.
STUDIES IN RESPIROMETRY
Authors: Thompson William R.
Published: May 2004

A machine has been described which combines volumetric and refractometric means of observing changes in carbon dioxide and oxygen concentrations and amounts in a closed system suitable for containing a respiring system. A means of thermoregulation has been described briefly. The theory upon which estimation is based has been outlined in considerable detail and generality; indicating how dependence upon absorption of gases by reagents can be eliminated completely, although they may be used in certain instances as a means of independent check. An experiment of this nature has been reported as an illustration of one use of the machine. Data of other experiments in which a moist environment was employed for the respiring system will be given in another communication.
SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO. II
Authors: Wilkes B. G. , Palmer Elizabeth T.
Published: May 2004

1. The pH-activity relationship of invertase has been studied in vivo and in vitro under identical external environmental conditions.

2. The effect of changing (H+) upon the sucroclastic activity of living cells of S. cerevisiae and of invertase solutions obtained therefrom has been found, within experimental error, to be identical.

3. The region of living yeast cells in which invertase exerts its physiological activity changes its pH freely and to the same extent as that of the suspending medium. It is suggested that this may indicate that this intracellular enzyme may perform its work somewhere in the outer region of the cell.

4. In using live cells containing maltase, no evidence of increased sucroclastic activity around pH 6.9, due to the action of Weidenhagen's α-glucosidase (maltase), was found.
THE ACTION OF X-RAYS ON EUPLOTES TAYLORI AND ASSOCIATED BACTERIA
Authors: Brown Morden G. , Luck J. Murray , Sheets Grace , Taylor C. V.
Published: May 2004

1. The minimum lethal dose of x-rays for Euplotes taylori was determined. Under the conditions of this investigation a 220 second exposure (2110 Roentgen units per second) was required to kill the protozoon. Much less exposure was sufficient to kill the associated bacteria. This difference in resistance permits the sterilization of protozoa with comparative ease.

2. Irradiation of Euplotes for 100 to 220 seconds caused a complete but temporary cessation of ciliary activity in many of the organisms, the percentage so affected increasing with the length of irradiation.

3. Pure cultures of Pseudomonas fluorescens and Bacillus coli, K13, separately irradiated, were found to be killed much more readily than protozoa,—the former in 15 seconds exposure (2530 Roentgen units per second) and the latter in 45 seconds.

4. The death of these organisms by irradiation was not due to the action of toxic products in the medium since separately irradiated media were not found to be toxic.

5. Irradiated bacteria were found unsatisfactory for the nutrition of Euplotes, previously sterilized either by irradiation or washing.
SPECIFIC NERVE IMPULSES FROM GUSTATORY AND TACTILE RECEPTORS IN CATFISH
Authors: Hoagland Hudson
Published: May 2004

1. Receptors in the lips and barbels of the catfish Ameiurus nebulosus Les. are very sensitive to mechanical stimuli, giving large rapid (A-type) impulses in fibers of the facial nerve in response to touching the receptive surfaces and to movements of the water in which the preparation is immersed.

2. The great sensitivity of the barbels and lips to currents of water and the bilateral symmetry of the distribution of sensitivity of the facial nerve may serve as a basis for observed rheotropic orientation in the catfish.

3. Acetic acid, NaCl, and meat juice, dissolved in the water bathing the barbels and lips, set up impulses of very small and barely detectable potential in the fibers of the facial nerve.

4. It is suggested that the specificity of impulses for the two sense modalities may be correlated with the large size of the cells of origin of the axons in the Gasserian ganglion supplying tactile receptors and the small size of the cells of origin in the geniculate ganglion sending axons to taste-buds.
THE CONVERSION OF FAT TO CARBOHYDRATE IN THE GERMINATING CASTOR BEAN
Authors: Murlin John R. ,   With the Assistance of William R. Murlin and Jean D. Watkeys
Published: May 2004

1. Respiration studies on single castor beans, made by means of the Brodie-Warburg method, at various times after the start of germination, as well as studies on groups of germinating beans over periods of 3 to 8 days, made by a simple procedure involving analysis of the respired air by the Haldane method, consistently give respiratory quotients from 0.30 to 0.58, indicating the conversion of the oil to carbohydrate.

2. The R.Q. varies with the stage of germination, the lowest point occurring when the new growth (hypocotyl) measures from 20 to 35 mm. in length.

3. The R.Q. of the young plant (cotyledons and hypocotyl), separated from the endosperm and studied in the same apparatus, varies from 0.78 to 1.00. It is invariably high enough to indicate considerable combustion of sugar. The R.Q. of the endosperm alone is low, but usually somewhat higher than that of the entire germinating structure.

4. On the same unit of moist weight the young plant (cotyledons and hypocotyl) produces about 2.6 times as much CO2 as the endosperm, whereas it absorbs only 1.3 times as much O2.
THE CONVERSION OF FAT TO CARBOHYDRATE IN THE GERMINATING CASTOR BEAN
Authors: Pierce H. B. , Sheldon Dorothy E. , Murlin John R.
Published: May 2004

1. Analyses for fat (ether extract), protein (N x 6.25), sugar including glucose, crude fiber, and ash have been made on all stages of the germinating castor bean up to 250 mm. length of hypocotyl and root system.

2. There is a continual decrease in the amount of fat present in the whole germinating seedling, and a continual increase in the amount of sugar up to about 40 per cent (dry weight) at a hypocotyl length of 80 to 140 mm., after which it decreases as crude fiber (cellulose) increases. The most rapid decrease in fat content coincides roughly with the most rapid increase of sugar.

3. The carbon balance between fat loss and carbohydrate (including fiber) gain is not at all close, except at the very beginning of growth. An undetermined residue occurs, which increases steadily along with the total carbohydrate and accounts for more and more of the carbon.

4. The protein content which in the ungerminated bean is about 26 per cent, at first falls a little and then rather steadily increases to reach nearly 35 per cent (dry) at the last stages studied. The most plausible explanation of this is the occurrence of more and more volatile substance which is lost in drying.

5. The ash increases irregularly but in the end shows about the same ratio of increase as the protein.

6. Respiration studies on several lots of these beans at different stages of germination exhibited the same low respiratory quotients as reported in Paper I. Comparing their composition at the end of the respiration period with that of corresponding stages when the period began, the chemical change can be compared with the respiratory exchange.

7. A trial balance of all the carbon changes including the respiratory carbon and protein carbon is not very satisfactory, because of our ignorance of the undetermined residue.

8. The respiratory quotient found can be accounted for quite satisfactorily on the assumption that two out of six molecules of ricinoleic acid are converted to cane sugar, one to cellulose, and three are oxidized.

9. The oxygen needed to produce the quantities of known carbohydrate found, added to that used for combustion, and the total subtracted from the observed loss from the respired air yields in two experiments a quantity which, combined with the excess carbon, suggests that the undetermined substance may be an oxidation product of pentose.
ON GUAIACOL SOLUTIONS
Authors: Shedlovsky Theodore , Uhlig Herbert H.
Published: May 2004

1. Measurements are reported on the distribution of sodium and potassium guaiacolates between guaiacol and water at 25°C.

2. The variation of the partition coefficients with the concentration is explained with the aid of the Debye-Hückel interionic attraction theory and the assumption that the salts are strong electrolytes in water and weak electrolytes in guaiacol.

3. The dissociation constants of sodium and potassium guaiacolates in guaiacol previously computed from electrical conductivity determinations are shown to be in agreement with the corresponding values obtained from the distribution measurements.

4. From theoretical considerations an equation is derived with which it is possible to predict the magnitude of the limiting partition coefficients from the dielectric constants of the solvents, the size of the solute ions, and the temperature.
THE GROWTH AND DURATION OF LIFE OF CELOSIA CRISTATA SEEDLINGS AT DIFFERENT TEMPERATURES
Authors: Edwards Thomas I. , Pearl Raymond , Gould Sophia A.
Published: May 2004

Daily measurements of hypocotyl length were made on Celosia cristata seedlings cultured in darkness under aseptic conditions at six constant temperatures between 14.5° and 40.5°C. At 40.5° roots did not penetrate the agar and only the hypocotyls that were supported by the wall of the test tube could be measured.

The growth curves were of the generalized logistic type, but of different degrees of skewness. The degree of symmetry of the growth curves was influenced by temperature. At the lower temperatures the maximal growth rate came relatively late in the grand period of growth; at successively higher temperatures it came progressively earlier.

The mean total time rate of growth (millimeter per diem) was found to be a parabolic function of the temperature.

The maximum rate of growth was found from the curve to be at 30.48°C. The maximum observed rate of growth, and the maximum yield, were found to be at 30°C.

At all temperatures above 14.5° the maximum growth activity fell in the second quarter of the whole growth period. At all temperatures tested other than 30°, and at all parts of the growth cycle, the growth yield as measured by height of hypocotyl at any given equivalent point was less than at 30°.

The total duration of life of the seedlings, and the duration of life after the end of the growth period (intermediate period) were inversely proportional to the mean total growth rate. The observations on Celosia cristata seedlings are thus in accord with the "rate of living" theory of life duration.

The optimal temperature for life duration is the minimum temperature, within the range of these observations.
CRYSTALLINE ACETYL DERIVATIVES OF PEPSIN
Authors: Herriott Roger M. , Northrop John H.
Published: May 2004

Crystalline pepsin has been acetylated by the action of ketene in aqueous solution at pH 4.07–5.5. As acetylation proceeds the activity decreases, the decrease being more rapid at pH 5.0–5.5 than at 4.0–4.5.

Three acetyl derivatives have been isolated from the reaction mixture and obtained in crystalline form. The crystal form of these derivatives is similar to that of pepsin.

Fractionation and solubility determinations show that these preparations are not mixtures or solid solutions of the original pepsin with an inactive derivative.

A compound which contains three or four acetyl groups and which has lost all of its original primary amino groups can be isolated after short acetylation. It has the same activity as the original pepsin. A second derivative containing six to eleven acetyl groups has also been isolated. It has about 60 per cent of the activity of the original pepsin. A third derivative having twenty to thirty acetyl groups and about 10 per cent of the activity of original pepsin can be isolated after prolonged acetylation. The 60 per cent active derivative on standing in strong acid solution loses some of its acetyl groups and at the same time regains the activity of the original pepsin. The compound obtained in this way is probably the same as the completely active three acetyl derivative obtained by mild acetylation. These results show that acetylation of three or four of the primary amino groups of pepsin causes no change in the specific activity of the enzyme but that the introduction of acetyl groups in other parts of the molecule results in a marked loss in activity.

The solubilities, amino nitrogen content, acetyl content, isoelectric point, and the specific activity have been determined by a variety of methods and found to be different from the corresponding properties of crystalline pepsin. The pH-activity curves, acid and alkali inactivation, and titration curves were not significantly different from the same respective properties of pepsin.
RESULTS OF IRRADIATING SACCHAROMYCES WITH MONOCHROMATIC ULTRA-VIOLET LIGHT
Authors: Oster R. H. , Arnold W. A.
Published: May 2004

Data obtained on yeast irradiated with monochromatic ultra-violet radiation has been analyzed for the number of quantum hits involved in the production of different degrees of inhibition of cell division, according to the method proposed by Mme. Curie (1929). Sufficient data are not available for a rigorous determination, but the calculated results tend to indicate that a multiple hit to kill relation is followed, that different numbers of hits are involved in the production of different degrees of inhibition, and that this number increases with increase in the degree of damage sustained.
THE LIGHT GROWTH RESPONSE AND THE GROWTH SYSTEM OF PHYCOMYCES
Authors: Castle E. S. , Honeyman A. J. M.
Published: May 2004

1. The Roscoe-Bunsen law holds for the light growth response of Phycomyces if the time component of stimulation is short. With exposures longer than a few seconds, the reaction time to light is determined by the intensity and not by the energy of the flash.

2. The possible nature of the very long latency in the response to light is considered in terms of the structure of the cell and its mechanism of growth. It is suggested that during the latency some substance produced by light in the protoplasm is transported centrifugally to the cell wall or outermost layer of protoplasm.

3. The total elongation occurring over a period of 1 to 2 hours is independent of flashes of light or temporary darkening. Light acts by facilitating some change already under way in the growth system, and during the principal phase of elongation is not a necessary or limiting factor for growth.

4. Judged by the reaction time, the original sensitivity is restored in the light system following exposure to light in about one-third the time required for equilibrium to be reattained in the growth system.
THE KINETICS OF PENETRATION
Authors: Jacques A. G.
Published: May 2004

The rate of entrance of H2S into cells of Valonia macrophysa has been studied and it has been shown that at any given time up to 5 minutes the rate of entrance of total sulfide (H2S + S-) into the sap is proportional to the concentration of molecular H2S in the external solution.

This is in marked contrast with the entrance of ammonia, where Osterhout has shown that the rate of entrance of total ammonia (NH3 + NR4+) does not increase in a linear way with the increase in the external concentration of NH3, but falls off. The strong base guanidine also acts thus.

It has been shown that the rate of entrance of H2S is best explained by assuming that it enters by diffusion of molecular H2S through the non-aqueous protoplasmic surface.

It has been pointed out that the simple diffusion requires that the rate of entrance might be expected to be monomolecular. Possible causes of the failure of H2S to follow this relationship have been discussed.
CHEMICAL RESTORATION IN NITELLA
Authors: Osterhout W. J. V.
Published: May 2004

Cells of Nitella exposed to distilled water lose their ability to produce action currents and to distinguish electrically between sodium and potassium. This ability was quickly restored by exposure to blood plasma deprived of calcium. Human blood and that of the cat, calf, and sheep gave essentially the same results.

The active agents appear to be organic substances.
THE POLARIZATION CAPACITY AND RESISTANCE OF VALONIA
Authors: Blinks L. R.
Published: May 2004

Alternating current measurements of the effective capacity and resistance of Valonia cells were undertaken to determine whether a static or polarization capacity was responsible for the large slow time curves of counter E.M.F. produced by the flow of direct current. (For this purpose it was necessary that the cells be in the regular state.) With external contacts at the ends of ceils, a large fall of impedance occurs over the frequency range from zero to 20,000 cycles, above which the impedance is low and essentially that of the cell interior.

As a first approximation to the cell circuit, a simple series-parallel circuit was employed in the bridge balance, with a resistance setting to represent the cell wall (and protoplasmic leakage), shunting the protoplasmic capacity in series with a resistance (sap plus polarization resistance). Both the capacity and its associated series resistance fall off regularly with frequency, giving curved lines on logarithmic plots against frequency, the slope of the resistance plot being steeper, and approaching that of f–1, although curved to it. These parallel roughly the behavior of a polarizing electrode, which is also shown.

Before concluding that the cell's capacity is therefore due to polarization, a further complication of the circuit was considered. This was the effect of the protoplasmic capacity distributed along the wall between the contacts. Both logically and experimentally it was shown that a distributed capacity, as represented by its approximate T-network of resistances and capacities invariant with frequency, could give rise to changes of capacity and series resistance with frequency which simulate to some extent the cellular phenomena.

Distributed capacity was therefore reduced in the cells by using shorter air-gaps between the contacts, or abolished by measuring impaled cells, in which the current flow across the protoplasm was entirely radial. These measurements showed a smaller, but still significant change of capacity and of equivalent resistance (in series with it) with frequency, somewhat less than with electrodes, and probably representing the true protoplasmic behavior. It is concluded that the cells display a certain degree of polarization capacity, possibly in parallel with a static capacity invariant with frequency. This might result from an insulating (e.g. lipoid) cell surface, having a residual differential permeability to ions. This structure is consistent with other evidence showing the cells to be chiefly permeable to non-ionized, lipoid-soluble materials, but still displaying electrical effects (conductance, potential difference, polarization) ascribable to ionic mobility.
THE DOUBLE REFRACTION OF CHITIN
Authors: Castle E. S.
Published: May 2004

The double refraction of the chitinous hair of the crayfish is positive with respect to the axis of the hair, and is largely caused by the arrangement of submicroscopic, elongated chitin particles parallel to this axis (form birefringence). Using a series of relatively unreactive liquids and fluid mixtures which permeate the chitin framework, the type of curve relating double refraction and refractive index of the imbibed fluid is found to depend greatly on the chemical nature of the fluid. Either a positive or a negative residual birefringence may be found, depending on the choice of imbibing liquid. Separation of form and crystalline elements in double refraction by means of Ambronn's imbibition technique is therefore unsafe in a system like chitin, where some type of oriented association of the imbibed molecules with the chitin framework is prevalent.
THE KINETICS OF SAPONIFICATION OF IODOACETIC ACID BY SODIUM HYDROXIDE AND BY CERTAIN ALKALINE BUFFER SOLUTIONS
Authors: Brdička R.
Published: May 2004

1. The rate of the saponification of iodoacetic acid in sodium hydroxide and alkaline buffer solutions yielding glycollic acid was measured by means of Heyrovský's polarographic method.

2. From the bimolecular velocity constants, increasing with the ionic strength of the solution, the Brönsted factor, F, which characterizes the primary salt effect, was calculated.

3. In the borate buffer solutions the monomolecular constants of the saponification were determined which, at values above the pH of neutralization of boric acid, show a proportionality to the concentration of hydroxyl anions. Below the pH of neutralization of boric acid, they are proportional to the concentration of borate anions.
CHANGES IN THICKNESS OF THE RED BLOOD CORPUSCLE MEMBRANE
Authors: Curtis Howard J.
Published: May 2004

Measurements of the static capacity per cm.2 of membrane for the red corpuscle as changed when the cells are made spherical by the addition of lecithin or rose bengal, show a slight increase of capacity, indicating a thinning of the membrane, although the change is not large enough to make it certain that it is real. Furthermore, the membrane capacity shows a slight decrease when spherical cells are swollen in hypotonic saline, indicating a thickening of the membrane, although the change is hardly outside the experimental error. The fact that there is no increase in capacity lends support to the theory that as the cell swells the membrane does not stretch but new material comes from the interior of the cell to make a new portion of the membrane.
ISOLATION FROM BEEF PANCREAS OF CRYSTALLINE TRYPSINOGEN, TRYPSIN, A TRYPSIN INHIBITOR, AND AN INHIBITOR-TRYPSIN COMPOUND
Authors: Kunitz M. , Northrop John H.
Published: May 2004

Methods are described for the isolation and crystallization of trypsinogen, trypsin, a substance which inhibits trypsin, and an inhibitor-trypsin compound. Analyses and some of the properties of these compounds are given.
COMPARATIVE STUDIES ON RESPIRATION
Authors: Gustafson F. G.
Published: May 2004

1. In the presence of 0.05 per cent dextrose the respiration of Aspergillus niger is increased by NaCl in concentrations of 0.25 to 0.5M, and by 0.5M CaCl2.

2. Stronger concentrations, as 2M NaCl and 1.25M CaCl2, decrease the respiration. The decrease in the higher concentrations is probably an osmotic effect of these salts.

3. A mixture of 19 cc. of NaCl and 1 cc. of CaCl2 (both 0.5M) showed antagonism, in that the respiration was normal, although each salt alone caused an increase.

4. Spores of Aspergillus niger did not germinate on 0.5M NaCl (plus 0.05 per cent dextrose) while they did on 0.5M CaCl2 (plus 0.05 per cent dextrose) and on various mixtures of the two. This shows that a substance may have different effects on respiration from those which it has upon growth.
THE RELATIVE PHYSIOLOGICAL EFFECTS OF ß- AND γ-RAYS UPON THE EGG OF NEREIS
Authors: Redfield Alfred C. , Bright Elizabeth M.
Published: May 2004

When Nereis eggs are exposed to radiations from a tube of radium emanation, the walls of which absorb all the α-rays, the resulting physiological change is produced by rays having a coefficient of absorption of the order of 23.9 cm.–1

This fact indicates that the physiological effect is due almost exclusively to ß-rays.

The γ-rays alone can produce the reaction. To produce equivalent physiological effects exposure to γ-rays alone must be approximately 60 times as long as exposure to ß- and γ-rays together.
CHANGES IN PROTOPLASMIC CONSISTENCY AND THEIR RELATION TO CELL DIVISION
Authors: Chambers Robert
Published: May 2004

1. The development of the amphiaster is associated with the formation of two semisolid masses within the more fluid egg substance.

2. The elongation of the egg during cleavage is possibly produced as a consequence of the mutual pressure of these two growing semisolid masses.

3. The division of the egg into two blastomeres consists essentially in a growth, within the egg, of two masses of material at the expense of the surrounding cytoplasm. When all the cytoplasm of the egg is incorporated in these two masses cleavage occurs.

4. After a certain period of time the semisolid masses revert to a more fluid state. In the eggs studied this normally occurs after the cleavage furrow has completed the separation of the two blastomeres. The formation of the furrow, however, may be prevented in various ways, upon which the egg reverts to a single spherical semifluid mass containing two nuclei.

5. An egg mutilated during its semisolid state (amphiaster stage) may or may not revert to a more fluid state. If the more solid state is maintained, the cleavage furrow persists and proceeds till cleavage is completed. If the mutilation causes the egg to revert to the more fluid state the furrow becomes obliterated and a new cleavage plane is subsequently adopted.

6. The nuclei of eggs in the semifluid state are able to alter their positions. In semifluid mutilated eggs the nuclei tend to move to positions which may assure symmetry in aster formation and cleavage.
ADRENALIN IN ANNELIDS
Authors: Gaskell J. F.
Published: May 2004

1. The sympathetic nervous system and the adjuvant adrenalin-secreting system are found in their earliest form in the annelid kingdom, and consist of cells situated in the central nervous system which are the common ancestors of both, and which are both secretory and nervous in function.

2. These cells are developed in the annelid kingdom parallel with the development of a contractile vascular system, which possesses muscles comparable in physiological actions with the muscle of the vertebrate heart.

3. This vascular muscle is regulated by the processes of the common ancestral cells as well as by their secretory activity.

4. In the primitive form contractile rhythm is an intrinsic property of cardiac muscle; its nerve supply regulates the rhythm, it does not initiate it. The beat is therefore myogenic, not neurogenic.

5. The contractile vascular system of annelids is mainly branchial in function. The vertebrate heart has been derived from it by the growing around of the lateral body folds to form a new ventral surface.
LABYRINTH AND EQUILIBRIUM
Authors: Maxwell S. S.
Published: May 2004

1. A dogfish from which all six ampullæ have been removed maintains its equilibrium; the righting reactions occur promptly; compensatory movements of the eyes occur in response to rotations in all planes except the horizontal; the compensatory position of the eyes is retained if the animal is held in an abnormal position. Both the static and dynamic functions of equilibrium continue, therefore, after complete removal of all the semicircular canals and all the ampullæ.

2. After complete removal of the otoliths from the vestibules without injury to the ampullæ the animal maintains its equilibrium in the water, rights itself promptly, and makes compensatory motions to rotations in all planes. If held in an abnormal position the compensatory position of the eyes is maintained. Both static and dynamic functions of equilibrium continue.

3. Destruction of both the semicircular canals and the otolith organs completely abolishes all compensatory movements and equilibrium reactions of labyrinthine origin.

4. It is pointed out that these observations do not justify the theory of Mach and Breuer that the ampullæ and semicircular canals are the organs for the dynamic functions of equilibrium, and that the otoliths are the organs for the static functions of equilibrium.

5. The new experiments recorded in this paper show that the ampullæ alone (without the otoliths) suffice for all the dynamic and all the static functions of equilibrium of the ear; and that the otolith organs (without the ampullæ) suffice for all the static and for all the dynamic functions of equilibrium of the ear with the exception of the response to a rotation of the animal in a horizontal plane.
STUDIES ON ENZYME ACTION
Authors: McGuire Grace , Falk K. George
Published: May 2004

The saccharogenic enzymes present in potato juice were studied. The actions were followed upon the substances present in the juice and upon added sucrose, maltose, and soluble starch.

Sucrase and amylase were found to be present in the juice. No indication of a maltase was obtained.

The sucrase showed optimum conditions for action at pH 4 to 5, the amylase at pH 6 to 7, both upon the starch present in the juice and upon added soluble starch.

The action of a yeast sucrase preparation upon the juice showed the presence of sucrose (or raffinose) in a concentration of the order of magnitude of 1 per cent.
THE PHOTOCHEMICAL NATURE OF THE PHOTOSENSORY PROCESS
Authors: Hecht Selig
Published: May 2004

1. In order to produce a response in Mya, the minimum amount of light energy required is 5.62 meter candle seconds. This energy follows the Bunsen-Roscoe law for the relation between intensity and time of exposure.

2. The necessary minimum amount of energy varies but little with the temperature; the temperature coefficient for 10°C. is 1.06.

3. In view of these facts it is concluded that the initial action of the light is photochemical in nature. This substantiates the hypothesis previously suggested to account for the mechanism of photoreception.

4. The constant energy requirement for stimulation of Mya shows that the traditional division of animals into those which respond to a constant source of light and those which respond to a rapidly augmented light is without any fundamental significance for sensory physiology.
QUANTITATIVE LAWS IN REGENERATION. I
Authors: Loeb Jacques
Published: May 2004

1. Equal masses of sister leaves of Bryophyllum calycinum produce equal masses of shoots and roots in equal time and under equal conditions.

2. The mass of shoots and roots produced by different masses of sister leaves in equal time and under equal conditions is approximately in direct proportion to the masses of the leaves.

3. When a piece of stem inhibits the production of shoots and roots in a leaf of Bryophyllum connected with it, the stem gains in mass and this gain in mass equals approximately the mass of shoots and roots the leaf would have produced if it had been detached from the stem.

4. This suggests that the inhibitory influence of the stem upon the formation of shoots and roots in the leaf is due to the fact that the material available for this process naturally flows into the stem.
INTENSITY AND THE PROCESS OF PHOTORECEPTION
Authors: Hecht Selig
Published: May 2004

1. In the photosensory process of Mya the latent period varies inversely as the intensity of the stimulating light.

2. Quantitative analysis of the data shows that the photochemical effect of the light is a logarithmic function of its intensity, the two variables being related to each other according to the well known "compound interest" law.

3. Comparison with previous experiments demonstrates that the Reciprocity Law of Bunsen and Roscoe applies to the photosensory process not only for the minimum energy required for a response, but for a much greater range of energy application as well.
STUDIES IN THE DYNAMICS OF HISTOGENESIS
Authors: Carey Eben J.
Published: May 2004

1. The region of most active mitosis per mm. of cross-section in the intestine is the entodermal epithelial tube. The mitotic figures primarily follow the path of a right-handed helix. In one of the twenty embryos the mitotic figures describe the path of a right-handed helix.

2. The region of least active or relatively passive growth per mm. of cross-section is the mesenchyme, derived from the splanchnic mesoderm surrounding the epithelial tube.

3. The rapid expansion, due to epithelial growth in a rotating spiral manner, of the intestinal lumen is greater than the activity manifest in the surrounding mesenchyme. This causes a pressure in the latter resulting in a flattening and elongation of the mesenchymal cells. The successive changes in shape of these cells through the spherical, ellipsoidal, and spindle cellular phases are seen. The mesenchymal wall decreases in thickness, due to tension caused by epithelial tubular dilation.

4. The rotating spiral growth of the epithelial cells causes the formation of a series of mesenchymal cellular and fibrillar concentric rings due to the centripetal force of the former.

5. The circular, smooth muscle cells are differentiated in the outer, more condensed margins of the ring. At these points the developing tensional stresses are greater than within the ring.

6. The inner circular smooth muscle coat is the first one differentiated and is incident to the rapid growth of the epithelial tube in diameter. The former soon tends to restrict the growth of the epithelial tube in diameter. The tube, pursuing the lines of least resistance, grows in length. During the period of rapid growth in length the outer longitudinal muscle coat is in the process of formation.

7. The tensional stresses to which the elongated strained mesenchymal cells are subjected appear to be a dynamic stimulus to smooth muscle differentiation.

8. From this study of a closely graded and progressive series of sections of intestinal development, the conclusion is drawn that muscle tissue is not self-differentiating, in the strict sense of the term, but that the tension of differential growth acts as the stimulus to smooth muscle differentiation.
THE EFFECT OF THE CONCENTRATION OF ENZYME ON THE RATE OF DIGESTION OF PROTEINS BY PEPSIN
Authors: Northrop John H.
Published: May 2004

1. In certain cases the rate of digestion of proteins by pepsin is not proportional to the total concentration of pepsin.

2. It is suggested that this is due to the fact that the enzyme in solution is in equilibrium with another substance (called peptone for convenience) and that the equilibrium is quantitatively expressed by the law of mass action, according to the following equation.

See PDF for Equation

It is assumed that only the uncombined pepsin affects the hydrolysis of the protein.

3. The hypothesis has been put in the form of a differential equation and found to agree quantitatively with the experimental results when the concentration of pepsin, peptone, or both is varied.

4. Pepsin inactivated with alkali enters the equilibrium to the same extent as active pepsin.

5. Under certain conditions (concentration of peptone large with respect to pepsin, and concentration of substrate relatively constant) the relative change in the amount of active pepsin is inversely proportional to the concentration of peptone and the equation simplifies to Schütz's rule.

6. An integral equation is obtained which holds for the entire course of the digestion (except for the first few minutes) with varying enzyme concentration. This equation is identical in form with the one derived by Arrhenius for the action of ammonia on ethyl acetate.

7. It is pointed out that there are many analogies between the action of pepsin on albumin solutions and the action of toxins on an organism.