bluuebunny/crossref_metadata_2025 huggingface dataset:
THE MOBILITY OF THE GELATINATE ION
Authors: Ferguson A. L. , Schluchter A. W.
Published: May 2004

1. Many measurements were made with the two systems

H2/NaOH C/NaOH C + x gm. gelatin/H2

H2/NaOH C/KCl (sat.)/NaOH C + x gm. gelatin/H2

in which x was varied from zero to more than enough for complete combination.

2. From these measurements the change in boundary potential with quantity of gelatin present was determined.

3. The boundary potentials were calculated by means of a modified form of the Henderson equation.

4. The results indicate that the mobility of the gelatinate ion is about 20.
SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO
Authors: Nelson J. M. , Palmer Elizabeth T. , Wilkes B. G.
Published: May 2004

1. A method is given whereby the course of hydrolysis of sucrose by live yeast cells may be followed with precision equal to that found when invertase solutions prepared from autolyzed yeast are used to cause inversion.

2. The practical value of the equation of Nelson and Hitchcock as a means of following the course of enzymic hydrolysis of sucrose is hereby extended.

3. The inversion of sucrose by live yeast cells and by extracted invertase has been quantitatively compared.

4. The course of hydrolysis of sucrose by the invertase of Fleischmann's yeast has been found to be identical in vivo and in vitro.
STIMULATION BY HYDROCHLORIC ACID AND BY THE NORMAL ALIPHATIC ACIDS IN THE SUNFISH EUPOMOTIS
Authors: Allison James B.
Published: May 2004

1. The reaction of the sunfish, Eupomotis gibbosus, to different concentrations of hydrochloric acid and of the first six members of the N aliphatic acids has been studied.

2. The stimulating efficiency of hydrochloric acid may best be related to the concentration of hydrogen ions produced by that acid.

3. The stimulating efficiency of the N aliphatic acids may best be correlated with the non-polar nature of a portion of the molecule, but it is necessary to consider the higher potential of the polar group of formic acid to account satisfactorily for its position in the series.

4. When equally effective concentrations of the N aliphatic acids are compared, formic acid is more effective at lower concentrations than at higher.

5. Per cent variation in response appears to be independent of the chemical environment to which the animal responded.
ELECTRIC PHASE ANGLE OF CELL MEMBRANES
Authors: Cole Kenneth S.
Published: May 2004

From the theory of an electric network containing any combination of resistances and a single variable impedance element having a constant phase angle independent of frequency, it is shown that the graph of the terminal series reactance against the resistance is an arc of a circle with the position of the center depending upon the phase angle of the variable element.

If it be assumed that biological systems are equivalent to such a network, the hypotheses are supported at low and intermediate frequencies by data on red blood cells, muscle, nerve, and potato. For some tissues there is a marked divergence from the circle at high frequencies, which is not interpreted.
THE ACCUMULATION OF ELECTROLYTES
Authors: Osterhout W. J. V. , Stanley W. M.
Published: May 2004

Inasmuch as attempts to explain accumulation by the Donnan principle have failed in the case of Valonia, a hypothesis of the steady state has been formulated to explain what occurs. In order to see whether this hypothesis is in harmony with physico-chemical laws attempts have been made to imitate its chief features by means of a model.

The model consists of a non-aqueous layer (representing the protoplasmic surface) placed between an alkaline aqueous phase (representing the external solution) and a more acid aqueous phase (representing the cell sap).

The model reproduces most of the features of the hypothesis. Attention may be called to the following points.

1. The semipermeable surface is a continuous non-aqueous phase.

2. Potassium penetrates by combining with an acid HX in the non-aqueous layer to form KX which in turn reacts with an acid HA in the sap to form KA. Since KX is little dissociated in the non-aqueous layer potassium appears to pass through it chiefly in molecular form.

3. The internal composition depends on permeability, e.g., sodium penetrates less rapidly than potassium and in consequence potassium predominates over sodium in the "artificial sap." The order of penetration in the model is the same as in Valonia, i.e., K > Na > Ca > Mg, and Cl > SO4, but the quantitative resemblance is not close, e.g., the difference between potassium and sodium, and chloride and sulfate is much less in the model.

4. The formation of KA and NaA in the sap raises its osmotic pressure and water enters.

5. The concentration of potassium and sodium and the osmotic pressure become much greater inside than outside. For example, potassium may become 200 times as concentrated inside as outside.

6. No equilibrium occurs but a steady state is reached in which water and salt enter at the same rate so that the composition of the sap remains constant as its volume increases.

7. Since no equilibrium occurs there is a difference of thermodynamic potential between inside and outside. At the start the thermodynamic potential of KOH is much greater outside than inside. This difference gradually diminishes and in the steady state has about the same value as in Valonia. The difference in pH value between the internal and external solutions is also similar in both cases (about 2 pH units).

8. Accumulation does not depend on the presence of molecules or ions inside which are unable to pass out.

One important feature of the hypothesis is not seen in the model: this is the exchange of HCO3 for Cl-. Experiments on this point are in progress.
THE OXYGEN CONSUMPTION OF ESCHERICHIA COLI DURING THE LAG AND LOGARITHMIC PHASES OF GROWTH
Authors: Martin Donald S.
Published: May 2004

The oxygen consumption of rapidly growing cultures of Esch. coli (S) have been measured by means of Fenn's respirometer.

The rate of oxygen consumption of a growing culture uniformly attains a phase of logarithmic increase before the growth curve of the organisms becomes logarithmic.

The rate of oxygen consumption per cell increases rapidly from the time of inoculation to a point of maximum respiration near the end of the lag phase of the growth curve, followed by a gradual decrease in the respiratory rate.

The surface area of the average cell when plotted against time passes through a point of maximum surface area which coincides with the point of maximum oxygen consumption per cell.

Figures obtained by different methods, CO2 output and heat production when reduced to the same units, agree remarkably well.
ON THE INTENSITY-TIME RELATIONS FOR STIMULATION BY ELECTRIC CURRENTS. I
Authors: Blair H. A.
Published: May 2004

Formulae are derived for the time-intensity relations for stimulation by direct currents using the following hypotheses: first, the current produces an excitatory effect whose rate of growth is proportional to the voltage; and second, the tissue reacts toward the normal state at a rate proportional to the amount of excitation. If p represents the local excitatory process numerically, the hypotheses are represented by the differential equation

See PDF for Structure.

where K and k are constants and V the applied voltage. For the stimulus to be adequate it is assumed that p must be built up to a certain liminal value. It appears as a deduction from the data that this liminal value is a function of the voltage of the form h ± αV where h and α are constants. α is zero or negligible for certain electrodes. αV is a measure of electrotonus or a similar phenomenon. Experimental data are discussed and are shown to agree satisfactorily with the derived formulae for stimulation both at the anode and cathode.
AUTOMATIC RECORDING OF MOVEMENTS OF PLANT ORGANS
Authors: Navez A. E. , Robinson T. W.
Published: May 2004

An automatic photographic recording apparatus is described. It uses plates sensitized to the red end of the spectrum for recording movements of organs of plants which cannot be photographed in white light. It enables one to obtain two types of pictures:

1. A "standing plate" picture where the successive positions of the organ to be registered are superimposed on the same plate, no motion being imparted to the plate.

2. A "moving plate" picture where, by means of a clock-controlled plate shifter, each successive picture is entirely separate from the preceding one.
PEPSIN ACTIVITY UNITS AND METHODS FOR DETERMINING PEPTIC ACTIVITY
Authors: Northrop John H.
Published: May 2004

Experimental methods are described for determining the activity of pepsin preparations by means of changes in the viscosity of gelatin, casein, edestin, and powdered milk solutions, and by the rate of formation of non-protein nitrogen from casein and edestin solutions, or by the increase in formol titration of casein, edestin or gelatin.

Activity units for pepsin are defined in terms of these measurements.
PULSATION FREQUENCY OF THE ADVISCERAL AND ABVISCERAL HEART BEATS OF CIONA INTESTINALIS IN RELATION TO TEMPERATURE
Authors: Wolf Ernst
Published: May 2004

The frequency of pulsation of the heart of Ciona intestinalis increases with temperature in both advisceral and abvisceral direction, according to the Arrhenius equation. The increase in pulsation is the same in both directions. The following µ values were obtained: 8,000–, 12,000+, 16,000, in several combinations, with critical temperatures at 10°, 15°, and 20°C. The values found are comparable with earlier findings for activity of the heart in different animals. This quantitative correspondence suggests anew the conception that temperature characteristics may be employed for recognition of controlling processes. The fact that the µ's and the critical temperature are the same for advisceral and abvisceral beats, indicates that the general metabolic condition of the two ends of the heart is the same in any one individual.
THE MECHANISMS OF TROPISTIC REACTIONS AND THE STRYCHNINE EFFECT IN DAPHNIA
Authors: Clarke G. L. , Wolf Ernst
Published: May 2004

1. Experiments with strychnine were performed to test two assumptions important in the development of a theory for the mechanisms involved in the tropisms exhibited by Daphnia.

2. After a brief interval in strychnine solution Daphnia exhibits a reversal of the primary sign (a) of phototropism, from negative to positive; and (b) of galvanotropism, from anodic to cathodic. In both cases the orientation of the body remains the same.

3. The mechanism responsible for the sign of phototropism and galvanotropism in Daphnia is therefore distinct from that underlying orientation.

4. Evidence is obtained indicating that changes in sign of tropism, produced by changes in illumination or by subjection to strychnine, involve the control of antagonistic muscles in the swimming appendages which are reciprocally innervated.
THE PHOTOCHEMICAL REACTION IN PHOTOSYNTHESIS
Authors: Emerson Robert , Arnold William
Published: May 2004

Measurements of photosynthesis were made in continuous and flashing light of high intensity, using cells varying in chlorophyll content. The amount of chlorophyll present per molecule of carbon dioxide reduced per single flash of light was found to be about 2480 molecules. The length of time required for one unit in the photosynthetic mechanism to complete the cycle of photochemical and Blackman reactions was found to be about 0.02 sec. at 25°C. The equation R = AIN was shown to give a good description of the rate of the photochemical reaction, when A is a velocity constant, I the intensity of light, and N the number of units in the photosynthetic mechanism.
THE EFFECTS OF RADIATIONS ON BIOLOGICAL SYSTEMS
Authors: Hussey Raymond , Thompson William R. , Tennant Robert , Campbell Nancy DuVal
Published: May 2004

The effect of high-frequency x-ray irradiation in prolongation of the larval stage of Drosophila melanogaster has been studied further, and evidence presented of the attainment of a maximum effect followed by a decrease to an almost level plateau in the course curve of average (median) prepupal period (ϕ) as a function of the period of irradiation (t) under otherwise fixed conditions. The variation of effects of the experimental treatment with age of the larvae at the time of irradiation has been demonstrated in both control and irradiated lots, and a strikingly decreased effect observed when ventilation was not supplied as usual.

Means of employment of a living system of this type as an indicator of effectiveness of radiation as in phantom depth or other distributional experiments have been presented and their use illustrated.
A STUDY OF THE EFFECTS OF CERTAIN VARIATIONS IN PREPARATION OF A STARCH SUBSTRATE IN AMYLASE VISCOSIMETRY
Authors: Wies Carl H. , McGarvey Sara M.
Published: May 2004

The results of employing different concentrations of starch and starch from different lots as substrates in the viscosimetric estimation of amylase concentration have been compared with the object of ultimate attainment of reproducible standards, independent of successive comparison.
FACTORS INVOLVED IN THE USE OF ORGANIC SOLVENTS AS PRECIPITATING AND DRYING AGENTS OF IMMUNE SERA
Authors: Merrill Malcolm H. , Fleisher Moyer S.
Published: May 2004

1. In concentrations of 70 to 75 per cent the organic solvents methyl, ethyl, and propyl alcohols, and acetone cause complete precipitation of serum proteins and produce maximum loss in solubility. We have referred to this concentration range as the critical concentration.

2. As the concentration of the solvents is increased from about 75 per cent precipitation continues complete but loss in solubility progressively decreases until at all concentrations above about 87 per cent the precipitates formed at room temperature are completely soluble.

3. The degree of resolubility of the precipitates formed even in these high concentrations of the organic solvent decreases as the temperature is raised and as the duration of exposure is increased.

4. At 5°C. the precipitates formed in all concentrations of these organic solvents are completely resoluble. Also these solvents exert maximum precipitating effect at lower temperature.

5. Maximum precipitating effect by these organic solvents occurs at about pH 6.0 precipitation becoming progressively less as the pH value is altered either way from this point.

6. The more concentrated the serum, the greater the proportion of protein present that will be precipitated by any given concentrations of organic solvent.

7. A method for preparing dry immune sera has been given. Such dried sera have been extracted with a number of organic compounds without loss in solubility or antibody activity.
THE EFFECT OF TEMPERATURE ON THE TITRATION CURVE OF CASEIN
Authors: Pertzoff V. A. , Carpenter S. C.
Published: May 2004

The influence of temperature on the titration curve of casein may be accounted for by the Bjerrum theory of ionization of ampholytes.
THE VISUAL INTENSITY DISCRIMINATION OF THE HONEY BEE
Authors: Wolf Ernst
Published: May 2004

1. Bees respond by a characteristic reflex to a movement in their visual field. By confining the field to a series of parallel stripes of different brightness it is possible to determine at any brightness of one of the two stripe systems the brightness of the second at which the bee will first respond to a displacement of the field. Thus intensity discrimination can be determined.

2. The discriminating power of the bee's eye varies with illumination in much the same way that it does for the human eye. The discrimination is poor at low illumination; as the intensity of illumination increases the discrimination increases and seems to reach a constant level at high illuminations.

3. The probable error of

See PDF for Equation

decreases with increasing I exactly in

the same way as does

See PDF for Equation

itself. The logarithm of the probable error

of ΔI is a rectilinear function of log I for all but the very lowest intensities. Such relationships show that the measurements exhibit an internal self-consistency which is beyond accident.

4. A comparison of the efficiency of the bee's eye with that of the human eye shows that the range over which the human eye can perceive and discriminate different brightnesses is very much greater than for the bee's eye. When the discrimination power of the human eye has reached almost a constant maximal level the bee's discrimination is still very poor, and at an illumination where as well the discrimination power of the human eye and the bee's eye are at their best, the intensity discrimination of the bee is twenty times worse than in the human eye.
ELECTROKINETIC PHENOMENA
Authors: Daniel Janet
Published: May 2004

1. The electrophoretic velocities of gelatin-, egg-albumin-, and gliadin-covered quartz particles in various alcohol-water solutions are, within the limits employed in usual experimental procedures, proportional to the field strength.

2. The electrophoretic mobilities of small, irregularly shaped quartz particles covered with an adsorbed film of protein in alcohol-water solutions are equal to the electroosmotic mobilities of the liquid past similarly coated flat surfaces. Hence the size and shape of such particles does not influence their mobilities, which depend entirely on the protein film.

3. The corrected mobility and hence presumably the charge of gelatin-covered quartz particles in solutions containing 35 per cent ethyl alcohol is proportional to the combining power of the gelatin; therefore the gelatin is adsorbed with the active groups oriented toward the liquid. The same is true in 60 per cent alcohol.

4. The charge calculated by means of the Debye-Henry approximation from the mobility of gelatin in solutions containing up to 35 per cent ethyl alcohol is, in the neighborhood of the isoelectric point, proportional to the combining power of the gelatin. Therefore the dielectric constant and the viscosity of the bulk of the medium may be used in the Debye-Henry approximation

Q = 6 π η r vm (1 + κ r)

to predict changes in charge from mobility.

5. In the neighborhood of the isoelectric point gelatin is probably completely ionized in buffered ethyl alcohol-water mixtures up to 60 per cent alcohol.

6. In the presence of ethyl alcohol the isoelectric point of gelatin is shifted toward smaller hydrogen ion activities. This shift, like that caused by alcohol in the isoelectric points of certain amino acids, is approximately linearly related to the dielectric constant of the medium.
THE KINETICS OF PENETRATION
Authors: Osterhout W. J. V.
Published: May 2004

An organic potassium salt, KG, passes from an aqueous phase, A, through a non-aqueous layer, B, into a watery solution, C. In C it reacts with CO2 to form KHCO3. The ionic activity product (K) (G) in C is thus kept at such a low level that KG continues to diffuse into C after the concentration of potassium becomes greater in C than in A. Hence potassium accumulates in C, the osmotic pressure rises, and water goes in. A steady state is eventually reached in which potassium and water enter C in a constant ratio.

The rate of entrance of potassium (with no water penetrating into C) may fall off in a manner approximately exponential. But water enters and may produce an exponential decrease in concentration. This suggests that the kinetics may be treated like that of two consecutive monomolecular reactions. Calculations made on this basis agree very well with the observed values.

The rate of penetration appears to be proportional to the concentration gradient of KG in the non-aqueous layer and in consequence depends upon the partition coefficients which determine this gradient.

Exchange of ions (passing as such through the non-aqueous layer) does not seem to play an important rôle in the entrance of potassium.

The kinetics of the model may be similar to that of living cells.
"GROWTH-PROMOTING SUBSTANCE" AND ELONGATION OF ROOTS
Authors: Navez A. E.
Published: May 2004

The vertical elongation of normal roots of Lupinus seedlings proceeds at constant rate over periods of 4 to 5 hours.

The decapitation of a root stops its elongation for a variable length of time, followed by a period of renewed elongation at a rate lower than that of the normal root.

The tipping of the decapitated root with a tip of a coleoptile of Zea induces a decrease in the rate of elongation of the root.

The same effect can be obtained with the diffusate from tips of coleoptile of Avena and to a lesser extent with diffusate of root tips.

The reduction in the rate of elongation of the root determined by diffusate from the lower half of the tip of a coleoptile placed horizontally is more pronounced than the inhibition elicited by the diffusate of the upper half of the same tip.

Various experiments with the diffusate of tips support the idea that under the conditions used the growth-promoting substance of the coleoptile tip or root tip inhibits the elongation of the decapitated root.
THERMOSTAT FOR LOWER TEMPERATURES
Authors: Stier T. J. B. , Crozier W. J.
Published: May 2004

Details are given concerning the construction and operation of relatively simple thermostats which permit maintaining precise temperatures down to 0°C. (with water), or temperatures above that of the ordinary room, and in which the temperature may be quickly altered at short intervals to new levels.
THE DIGESTION AND INACTIVATION OF MALTASE BY TRYPSIN AND THE SPECIFICITY OF MALTASES
Authors: Tauber Henry , Kleiner Israel S.
Published: May 2004

1. The maltase of saliva and that of E. coli (B. coli communis) hydrolyze maltose but not α-methylglucoside or sucrose and are therefore to be considered glucomaltases.

2. Maltase is rapidly and completely inactivated and digested by trypsin.
ON THE RELATION BETWEEN MEASUREMENTS OF INTENSITY DISCRIMINATION AND OF VISUAL ACUITY IN THE HONEY BEE
Authors: Wolf Ernst
Published: May 2004

1. Bees respond by a characteristic reflex to a movement of their visual field. By confining the field to a series of parallel stripes of two alternating different brightnesses it is possible to determine for any width of stripe, at any brightness of one of the two sets of stripes, the brightness of the second at which the bee will first respond to a displacement of the field. Thus the relations between visual acuity and intensity discrimination can be studied.

2. For each width of stripe and visual angle subtended by the stripe the discrimination power of the bee's eye for different brightnesses was studied. For each visual acuity the intensity discrimination varies with illumination in a characteristic, consistent manner. The discrimination is poor at low illuminations; as the intensity of illumination increases the discrimination increases, and reaches a constant level at high illuminations.

3. From the intensity discrimination curves obtained at different visual acuities, visual acuity curves can be reconstructed for different values of ΔI/I. The curves thus obtained are identical in form with the curve found previously by direct test for the relation between visual acuity and illumination.
ANALYSIS OF THE GEOTROPIC ORIENTATION OF YOUNG RATS. VII
Authors: Crozier W. J. , Pincus G.
Published: May 2004

The intraperitoneal injection of standard young rats of race A with 2/5 cc. of adrenalin chloride 1:50,000 results in increased speed of geotropically oriented creeping upon an inclined surface. It was expected that the effect of such increased frequency of stepping must be analogous to that due to imposition of added loads carried by the rats during geotropic progression. This is verified. The curve connecting θ with log sin α is distorted, under adrenalin, so as to be comparable to that obtained with an added mass of approximately 2.5 gm. upon the young rat's saddle; the threshold slope of surface for orientation is accordingly lowered, from α = 20° to α = 12.5°; at the new threshold slope of surface the mean orientation angle θ is the same as in the absence of adrenalin at the corresponding threshold slope of surface.

The total variation of performance is significantly increased in the injected rats, and at given slope of surface the variation is slightly increased. The proportionate modifiable variation of response is quite unaffected by the distortion of the θ – α curve, and is the same as in standard young A rats untreated or carrying additional loads.

It is pointed out that for the consideration of the problem as to whether a given experimental treatment, or a given natural situation, affects in any way the variation of performance of a living system, it is necessary to obtain indices of variability which involve the expression of variation of performance as a function of measured conditions governing the performance.
THE REACTIONS OF HALICYSTIS AND OF VALONIA TO INJECTIONS OF CERTAIN PROTEINS
Authors: East E. M. , White Benjamin
Published: May 2004

It is shown (1) that Valonia and Halicystis cells exhibit varying degrees of tolerance to injections of animal peptone, animal proteose, crystallized egg albumen, and diphtheria toxin; (2) that Valonia cells display decreased tolerance to egg albumen in increasing dosages, although Halicystis is completely tolerant of the highest dosage used; (3) that the mortality curves of Valonia injected with egg albumen and of both Valonia and Halicystis injected with diphtheria toxin show the delayed effect characteristic of laboratory mammals when treated similarly; (4) that Valonia cells injected twice with egg albumen exhibit no change in susceptibility to its effects; and (5) that neither species of algae gives evidence of having formed antibodies against the antigens used.
THE INACTIVATION OF BACTERIOPHAGE BY MERCURY BICHLORIDE; THE REACTIVATION OF BICHLORIDE-INACTIVATED PHAGE
Authors: Krueger A. P. , Baldwin D. M.
Published: May 2004

1. The inactivation of antistaphylococcus bacteriophage suspended in infusion broth at pH 7.6 and 22°C. by HgCl2 proceeds according to the equation dP/dt = k [HgCl2] [Po – Pi] over the range studied.

2. This inactivation can be reversed by precipitation of Hg++ with H2S. In the present experiments the inactivation was carried out until only some 5 per cent of the initial phage remained active. After reactivation the [P] had increased to 100 per cent of the initial [P].
THE EFFECT OF WATER CONTENT UPON THE RATE OF HEAT DENATURATION OF CRYSTALLIZABLE EGG ALBUMIN
Authors: Barker H. Albert
Published: May 2004

1. The denaturation rate of partially dried crystallizable egg albumin is greatly decreased by decreasing its water content.

2. The temperature of denaturation, defined as the temperature at which half of the protein becomes insoluble in distilled water after a definite time of heating, is a linear function of the relative humidity with which the protein is in equilibrium.

3. By applying the Arrhenius equation it is shown that the rate of heat denaturation at a given temperature is an exponential function of the relative humidity.

4. The application of the observed relations to the analysis of the mechanism of thermal death of microorganisms is suggested.

5. The water content of native and heat-denatured egg albumin is determined as a function of the relative humidity of water vapor. It is shown that the heat-denatured modification takes up approximately 80 per cent as much water at all relative humidities as does native egg albumin.
THE REFRACTIVE INDICES OF WHOLE CELLS
Authors: Castle E. S.
Published: May 2004

Refractive indices of intact sporangiophores of Phycomyces were computed from measurements of focal length and radius of curvature of the cells. For the six cells studied, effective values of n were obtained ranging from 1.35 to 1.40. The average effective n was 1.38. Senn's determination of refractive indices of other plants cells gave much higher values: n = 1.37 to 1.52. The precision of the method and possible sources of this discrepancy are discussed.
THE PHYSICAL BASIS OF THE POSITIVE PHOTOTROPISM OF PHYCOMYCES
Authors: Castle E. S.
Published: May 2004

A physical basis is demonstrated, in the case of a cylindrical cell illuminated with parallel light from one side, for greater photochemical action in the half of the cell farthest from the source of light, when the cell is surrounded by a medium of refractive index less than that of the cell. Factors governing the balance and magnitude of unequal action of light in the two halves of the cell are: the refractive index of the cell, the cell radius, and the absorption coefficient of the intracellular pigment. A limiting value of absorption coefficient is deduced which cannot be exceeded in cells of a particular size showing positive phototropism. In terms of this mechanism the positive phototropism of Phycomyces in air is explained.
THE ACTION OF THE PLANT GROWTH HORMONE
Authors: Bonner James
Published: May 2004

1. Sections of Avena coleoptiles are found to show a considerable elongation when suspended in solutions of growth substance.

2. This elongation does not take place in the absence of O2 and is inhibited by KCN and phenylurethane.

3. The rate of respiration of sections of coleoptiles is increased by the addition of growth substance in concentrations which cause growth. High concentrations of growth substance inhibit growth and also respiration.

4. The increase in respiration is inhibited by KCN and phenylurethane in the concentrations which inhibit normal respiration. These concentrations are the same as those which inhibit growth.

5. From 2, 3, and 4, it seems possible that the increase in respiration caused by growth substance may be an essential part of its action in growth.
ELECTRICAL RESPONSES FROM LATERAL-LINE NERVES OF FISHES. III
Authors: Hoagland Hudson
Published: May 2004

Evidence indicates that lateral-line fibers, other than those mediating the "spontaneous" activity of the lateral-line receptors, are brought into play in response to pressure stimuli in catfish and in trout.

The distribution and mode of stimulation of mechanoreceptors along the lateral-lines of trout and catfish are discussed in relation to the natural activities of these forms.
ABSORPTION OF PEPSIN BY CRYSTALLINE PROTEINS
Authors: Northrop John H.
Published: May 2004

Crystalline proteins, such as edestin or melon globulin, remove pepsin from solution. The pepsin protein is taken up as such and the quantity of protein taken up by the foreign protein is just equivalent to the peptic activity found in the complex. The formation of the complex depends on the pH and is at a maximum at pH 4.0.

An insoluble complex is formed and precipitates when pepsin and edestin solutions are mixed and the maximum precipitation is also at pH 4.0. The composition of the precipitate varies with the relative quantity of pepsin and edestin. It contains a maximum quantity of pepsin when the ratio of pepsin to edestin is about 2 to 1. This complex may consist of 75 per cent pepsin and have three-quarters of the activity of crystalline pepsin itself. The pepsin may be extracted from the complex by washing with cold N/4 sulfuric acid. If the complex is dissolved in acid solution at about pH 2.0 the foreign protein is rapidly digested and the pepsin protein is left and may be isolated.

The pepsin protein may be identified by its tyrosine plus tryptophane content, basic nitrogen content, crystalline form and specific activity.
ELECTRICAL RESPONSES FROM THE LATERAL-LINE NERVES OF FISHES
Authors: Hoagland Hudson
Published: May 2004

The spontaneous discharge of impulses from the lateral-line nerves of trout and catfish has been examined.

1. Broken endings of nerve fibers supplying receptors of the lateral-lines of trout and catfish may be the source of a repetitive discharge of nerve impulses.

2. This injury discharge occurs more frequently in trout and may mask the spontaneous discharge from the receptor cells. Experiments indicate that the latter discharge is not the result of injury.

3. The injury discharge ceases in from 10 to 15 minutes. The spontaneous receptor discharge in trout may continue for an hour if the circulation remains intact. The receptor response also fails in from 10 to 15 minutes after failure of the circulation.

4. The receptor discharge, the injury discharge, or the summed discharges frequently become synchronized. The excitability of the fibers of the nerve trunk appears to vary synchronously, so that nerve impulses initiated in fibers from tactile receptors not contributing to the spontaneous discharge can be conducted only during the part of the cycle occupied by the spontaneous discharge.
INTERMITTENT STIMULATION BY LIGHT
Authors: Hecht Selig , Shlaer Simon , Verrijp Cornelis D.
Published: May 2004

An apparatus and a procedure are described to measure the critical frequency of flicker using different portions of the eye. The observer, looking through a pupil of fixed dimensions, views a field of 2° whose illumination is periodically interrupted and which is surrounded by a field of 10° whose illumination is continuous but otherwise identical with the interrupted field. Various parts of the apparatus are concerned with controlling and recording the retinal position of the field, its intensity, its spectral composition, and the frequency of interruption of its illumination. The procedure is so simplified and regulated that a complete set of readings over the whole intensity range of vision can be made at one sitting without fatigue or strain.
MOLECULAR WEIGHT, MOLECULAR VOLUME, AND HYDRATION OF PROTEINS IN SOLUTION
Authors: Kunitz M. , Anson M. L. , Northrop John H.
Published: May 2004

1. The gram molecular weight of a substance may be calculated from the osmotic pressure of its solution.

2. The radius of the hydrated molecule and, hence, the gram molecular volume of the hydrated solute may be determined from diffusion measurements. The hydration of the molecules may, therefore, be calculated from osmotic pressure and diffusion measurements.

3. Hydration may also be determined by viscosity measurements. Hydration of crystalline hemoglobin, crystalline trypsin, and gelatin have been determined by these methods and found to be as follows:

See PDF for Structure
THE EQUILIBRIA BETWEEN NATIVE AND DENATURED HEMOGLOBIN IN SALICYLATE SOLUTIONS AND THE THEORETICAL CONSEQUENCES OF THE EQUILIBRIUM BETWEEN NATIVE AND DENATURED PROTEIN
Authors: Anson M. L. , Mirsky A. E.
Published: May 2004

The denaturation of hemoglobin by salicylate in neutral solution is completely reversible.

There is a mobile equilibrium between native and denatured hemoglobin in neutral salicylate solution. The higher the salicylate concentration the greater is the percentage denaturation.

When there is a mobile equilibrium between the native and denatured forms of a protein, denaturation is caused by the addition of any substance which has a greater affinity for the denatured than for the native form.

Theoretically the heat of denaturation must vary with the denaturing agent and must depend on the heat of combination of the denaturing agent with the protein.
ON THE RELATION BETWEEN TOXICITY, RESISTANCE, AND TIME OF SURVIVAL, AND ON RELATED PHENOMENA
Authors: Reiner L.
Published: May 2004

1. A relation between toxicity, resistance, and time of survival has been derived on the basis of the assumption that the time is a function of a parameter which is the difference between the toxicity and the resistance. Toxicity and resistance act like forces which can maintain an equilibrium-like (or stationary) state. If the equilibrium is upset, the time at which the event (death) occurs is proportional to the logarithm of the difference between toxicity and resistance.

2. It was found that if values proportional to the resistance are calculated with the proposed equation and the percentage mortality plotted against them (instead of against the time as is usual) symmetrical curves are obtained even though the corresponding mortality-time curves are asymmetrical. Assuming that the resistance varies like an error, that is, according to probability rules, theoretical mortality-time curves, similar to the experimental curves, can be constructed from the proposed equations.

3. In the case of a toxic agent acting on a unicellular organism suspended in solution, the toxicity is proportional to the adsorbed amount of the agent, as calculated with the aid of the Langmuir equation. In small concentration ranges the toxicity can be taken as approximately proportional to the concentration.

4. The variation of the temperature affects mainly the constant a which is a function of the temperature similar to that of the velocity constant of a chemical reaction (Arrhenius' law).

5. The proposed equation has been tested in four different combinations of the variables, concentration, resistance, time, and temperature. The agreement with the experiments is satisfactory.

6. Any noxious agent acting on a unicellular organism may be characterized by three constants: r, the resistance, which is the threshold value at which the agent is still fatally toxic for the organism; a, the reciprocal of the rate constant determining the specific rate (that is, the time corresponding to a difference of 1 between the toxicity and the resistance); and finally the constant γ of the function representing the relation between toxicity and concentration.
THE KINETICS OF PENETRATION
Authors: Osterhout W. J. V. , Kamerling S. E. , Stanley W. M.
Published: May 2004

Some of the factors affecting penetration in living cells may be advantageously studied in models in which the organic salts KG and NaG diffuse from an aqueous solution A, through a non-aqueous layer B (representing the protoplasmic surface) into an aqueous solution C (representing the sap and hence called artificial sap) where they react with CO2 to form KHCO3 and NaHCO3. Their relative proportions in C depend chiefly on the partition coefficients and on the diffusion constants in the non-aqueous layer. But the ratio is also affected by other variables, among which are the following:

1. Temperature, affecting diffusion constants and partition coefficients and altering the thickness of the unstirred layers by changing viscosity.

2. Viscosity (especially in the non-aqueous layers) which depends on temperature and the presence of solutes.

3. Rate of stirring, which affects the thickness of the unstirred layers and the transport of electrolyte in those that are stirred.

4. Shape and surface area of the non-aqueous layer.

5. Surface forces.

6. Reactions occurring at the outer surface such as loss of water by the electrolyte or its molecular association in the non-aqueous phase. The reverse processes will occur at the inner surface and here also combinations with acids or other substances in the "artificial sap" may occur.

7. Outward diffusion from the artificial sap. The outward movement of KHCO3 and NaHCO3 is small compared with the inward movement of KG and NaG when the concentrations are equal. This is because the partition coefficients3 of the bicarbonates are very low as compared with those of NaG and KG.

Since CO2 and HCO3- diffuse into A and combine with KG and NaG the inward movement of potassium and sodium falls off in proportion as the concentration of KG and NaG is lessened.

8. Movement of water into the non-aqueous phase and into the artificial sap. This may have a higher temperature coefficient than the penetration of electrolytes.

9. Variation of the partition coefficients with concentration and pH.

Many of these variables may occur in living cells. (It happens that the range of variation in the ratio of potassium to sodium in the models resembles that found in Valonia.)
KINETICS OF PENETRATION
Authors: Osterhout W. J. V. , Kamerling S. E. , Stanley W. M.
Published: May 2004

In some living cells the order of penetration of certain cations corresponds to that of their mobilities in water. This has led to the idea that electrolytes pass chiefly as ions through the protoplasmic surface in which the order of ionic mobilities is supposed to correspond to that found in water.

If this correspondence could be demonstrated it would not prove that electrolytes pass chiefly as ions through the protoplasmic surface for such a correspondence could exist if the movement were mostly in molecular form.

This is clearly shown in the models here described. In these the protoplasmic surface is represented by a non-aqueous layer interposed between two aqueous phases, one representing the external solution, the other the cell sap.

The order of penetration through the non-aqueous layer is

Cs > Rb > K > Na > Li.

This will be recognized as the order of ionic mobilities in water. Nevertheless the movement is mostly in molecular form in the nonaqueous layer (which is used in the model to represent the protoplasmic surface) since the salts are very weak electrolytes in this layer.

The chief reason for this order of penetration lies in the fact that the partition coefficients exhibit the same order, that of cesium being greatest and that of lithium smallest.

The partition coefficients largely control the rate of entrance since they determine the concentration gradient in the non-aqueous layer which in turn controls the process of penetration. The relative molecular mobilities (diffusion constants) in the non-aqueous layer do not differ greatly. The ionic mobilities are not known (except for K+ and Na+) but they are of negligible importance, since the movement in the non-aqueous layer is largely in molecular form. They may follow the same order as in water, in accordance with Walden's rule.

Ammonium appears to enter faster than its partition coefficient would lead us to expect, which may be due to rapid penetration of NH3. This recalls the apparent rapid penetration of ammonium in living cells which has also been explained as due to the rapid penetration of NH3.

Both observation and calculation indicate that the rate of penetration is not directly proportional to the partition coefficient but increases somewhat less rapidly.

Many of these considerations doubtless apply to living cells.
BLAIR'S "CONDENSER THEORY" OF NERVE EXCITATION
Authors: Rushton W. A. H.
Published: May 2004

Blair's recent theory of excitation is analysed with the following conclusions:

1. The theory is inapplicable to currents of long duration; i.e., slowly increasing currents and the opening excitation.

2. The theory is a modification of the condenser theory of excitation but the modification is to be rejected on three grounds:

(a) The modification has no obvious physical significance.

(b) It does not in fact remedy the divergence between calculation and observation.

(c) It leads to certain conclusions of a surprising kind which are contrary to observed fact.

3. The qualitative value of the condenser theory is demonstrated by the fairly close agreement between calculation and observation over a considerable field of enquiry.
THE TIME CURVE OF FACET DETERMINATION IN AN ULTRABAR STOCK OF DROSOPHILA MELANOGASTER
Authors: Hersh A. H.
Published: May 2004

By a dissection of the data obtained by Driver on the effective periods at different temperatures in males and females of an ultrabar stock of Drosophila melanogaster it has been found that a symmetrical sigmoid curve satisfactorily describes the time course of the facet-determining reaction. Consequently the differences between members of the bar series in regard to this reaction do not represent merely developmental arrests of the process at some greater or lesser distance from a common upper asymptote, but the termination of the process is approached asymptotically. The velocity constant/temperature relation shows a discontinuity in the neighborhood of 21° which may be causally related to the change in the position of the effective period from the second to the third instar. The velocity constant apparently does not conform to the well known Arrhenius equation in its relation to temperature.
INACTIVATION OF CRYSTALLINE TRYPSIN
Authors: Kunitz M. , Northrop John H.
Published: May 2004

1. The rate of inactivation of crystalline trypsin solutions and the nature of the products formed during the inactivation at various pH at temperatures below 37°C. have been studied.

2. The inactivation may be reversible or irreversible. Reversible inactivation is accompanied by the formation of reversibly denatured protein. This denatured protein exists in equilibrium with the native active protein and the equilibrium is shifted towards the denatured form by raising the temperature or by increasing the alkalinity. The decrease in the fraction of active enzyme present (due to the formation of this reversibly denatured protein) as the pH is increased from 8.0 to 12.0 accounts for the decrease in the rate of digestion of proteins by trypsin in this range of pH.

3. The loss of activity at high temperatures or in alkaline solutions, just described, is very rapid and is completely reversible for a short time only. If the solutions are allowed to stand the loss in activity becomes gradually irreversible and is accompanied by the appearance of various reaction products the nature of which depends upon the temperature and pH of the solution.

4. On the acid side of pH 2.0 the trypsin protein is changed to an inactive form which is irreversibly denatured by heat. The course of the reaction in this range is monomolecular and its velocity increases as the acidity increases.

5. From pH 2.0 to 9.0 trypsin protein is slowly hydrolyzed. The course of the inactivation in this range of pH is bimolecular and its velocity increases as the alkalinity increases to pH 10.0 and then decreases. As a result of these two reactions there is a point of maximum stability at about pH 2.3.

6. On the alkaline side of pH 13.0 the reaction is similar to that in strong acid solution and consists in the formation of inactive protein. The course of the reaction is monomolecular and the velocity increases with increasing alkalinity. From pH 9.0 to 12.0 some hydrolysis takes place and some inactive protein is formed and the course of the reaction is represented by the sum of a bi- and monomolecular reaction. The rate of hydrolysis decreases as the solution becomes more alkaline than pH 10.0 while the rate of formation of inactive protein increases so that there is a second point at about pH 13.0 at which the rate of inactivation is a minimum. In general the decrease in activity under all these conditions is proportional to the decrease in the concentration of the trypsin protein. Equations have been derived which agree quantitatively with the various inactivation experiments.