bluuebunny/crossref_metadata_2025 huggingface dataset:
STIMULATION OF FUNDULUS BY HYDROCHLORIC AND FATTY ACIDS IN FRESH WATER, AND BY FATTY ACIDS, MINERAL ACIDS, AND THE SODIUM SALTS OF MINERAL ACIDS IN SEA WATER
Authors: Allison J. B. , Cole William H.
Published: May 2004

1. Fundulus heteroclitus was found to be a reliable experimental animal for studies on chemical stimulation in either fresh or sea water.

2. The response of Fundulus to hydrochloric, acetic, propionic, butyric, valeric, and caproic acids was determined in fresh water, while the same acids plus sulfuric and nitric, as well as the sodium salts of the mineral acids, were tested in sea water.

3. Stimulation of Fundulus by hydrochloric acid in fresh water is correlated with the effective hydrogen ion concentration. Stimulation by the n-aliphatic acids in the same environment is correlated with two factors, the effective hydrogen ion concentration and the potential of the non-polar group in the molecule. However, as the number of CH2 groups increases the stimulating effect increases by smaller and smaller amounts, approaching a maximum value.

4. Stimulation of Fundulus by hydrochloric, sulfuric, and nitric acids in sea water is correlated with the forces of primary valence which in turn are correlated with the change in hydrogen ion concentration of the sea water. The n-aliphatic acids increase in stimulating efficiency in sea water as the length of the carbon chain increases, but a limiting value is not reached as soon as in fresh water.

5. Only a slight difference in stimulation by hydrochloric acid is found in sea water and in fresh water. However, there is a significant difference in stimulation by the fatty acids in fresh and in sea water, which is partly explained by the different buffering capacities of the two media. It is to be noted that in the same environment two different fish, Fundulus and Eupomotis, give different results, while the same fish (Fundulus) in two different environments responds similarly to mineral acids but differently to fatty acids. These results illustrate that stimulation is a function of the interaction between environment and receptors, and that each is important in determining the response.

6. Stimulation by sodium chloride, nitrate, and sulfate is correlated with equivalent concentrations of the salts added to sea water, or with the forces of primary valence. Although the threshold for stimulation by the salts is considerably higher than for the acids, the efficiency of stimulation by the salts is greater.
MANOMETRIC MEASUREMENTS OF PHOTOSYNTHESIS IN THE MARINE ALGA GIGARTINA
Authors: Emerson Robert , Green Lowell
Published: May 2004

A manometric method for measuring photosynthesis in marine algae is described.

Photosynthesis in the red alga Gigartina harveyana is shown to be similar in all important respects to photosynthesis in Chlorella and other Chlorophyceae.
ELECTRICAL CONTROL OF RHIZOID FORMATION IN THE RED ALGA, GRIFFITHSIA BORNETIANA
Authors: Schechter Victor
Published: May 2004

1. Direct galvanic current of 10 to 40 microamperes per square millimeter of cross-section of medium results in anodal determination of rhizoid origin in the differentiated cells of the red alga Griffithsia bornetiana. The current is most effective near the upper end of the range.

2. Within the range used there is an increase in the number of rhizoids produced with increase in current intensity and a decrease in size of rhizoids.

3. Currents of lower intensity require a longer time to produce these effects than comparatively high currents.

4. The orientation of the plants in the electrical field seems to affect the number of rhizoids produced, in that plants with apexes toward the anode produce more rhizoids.

5. Together with anodal rhizoid determination there is migration of chromatophores toward the anodal side of each cell.

6. Displacement of chromatophores (and other cytoplasmic bodies) by the centrifuge does not affect the point of rhizoid origin, but does affect the shoots.

7. Together with anodal determination of rhizoids the algal filaments become graded in color, from bright pink toward the cathode to pale tan toward the anode.

8. Evidence is presented to show that this is not due to a pH change, but to a loss of pigment by chromatophores toward the anode and electrophoresis of the pigment toward the cathode.

9. In conclusion the probability is pointed out that the current acts in morphogenesis by moving particles of different charge.
THE RATE OF ESCAPE OF HEMOGLOBIN FROM THE HEMOLYZED RED CORPUSCLE
Authors: Fricke Hugo
Published: May 2004

A theoretical treatment is given of the rate of escape of hemoglobin from the hemolyzed red corpuscle. For complete permeability of the surface, as may perhaps be produced by strong lysins, the time taken for the hemoglobin to decrease to 10 per cent of its original concentration is calculated to be 0.16 seconds (for the human cell). For dilute saponin, giving complete lysis of human cells in 3 minutes, Ponder found a time of escape of 4 seconds, from which the permeability of the membrane to the pigment is calculated to be µH = 5 x 10–5 cm./sec.
THE CHLOROPHYLL UNIT IN PHOTOSYNTHESIS
Authors: Arnold William , Kohn Henry I.
Published: May 2004

In six species of plants, representing four phyla, the minimum number of chlorophyll molecules present for each molecule of carbon dioxide reduced appears to lie between 2,000 and 3,000. This finding suggests the existence of a chlorophyll unit.
CONDUCTION IN NERVE FIBRES
Authors: Blair H. A.
Published: May 2004

Data by E. A. Blair and Erlanger on the voltage-capacity curves and the nerve impulse velocities of each of several fibres in the same nerve trunk are related to Rashevsky's equation for the velocity of transmission in nerve. The results lend support to Rashevsky's analysis. Other empirical relations between the velocity and the parameters of the excitation equations indicate the correctness of the hypothesis that the action current is the primary factor in transmission, which process is carried on by the electrical excitation of successive regions of the nerve fibre by means of its action current according to the ordinary laws of electrical excitation.
STUDIES ON THE GROWTH HORMONE OF PLANTS
Authors: Thimann Kenneth V.
Published: May 2004

1. It is shown that when plant tissues are ground with water the growth substance contained therein is inactivated by the oxidizing enzymes.

2. A simple method of extraction is described which enables the quantitative determination of growth substance in such tissues.

3. The amount and distribution of growth substance in the Avena coleoptile is determined by this method, and it is shown that while the substance does not diffuse out from the lower parts of the coleoptile, it is nevertheless present in considerable amounts, the concentration decreasing steadily with the distance from the tip.

4. Growth substance is also present in considerable amounts in Avena roots, and here also its concentration decreases steadily with distance from the tip.

5. The amount of growth substance diffusing out of root tips into dextrose agar, even during long periods of time, is not greater than the amount obtainable by direct extraction. Actual production in the root tip therefore either does not take place at all, or else takes place under quite different conditions from the production in the tip of the coleoptile.
ELECTRICAL RESPONSES FROM THE LATERAL-LINE NERVES OF FISHES
Authors: Hoagland Hudson
Published: May 2004

Records of spontaneous discharge of nerve impulses, similar to that previously described in catfish and in trout, have been obtained from lateral-line nerves of goldfish and perch, by the use of concentric micro electrodes slipped under the nerve in situ. These impulses have been followed into the central nervous system. They enter the tuberculum acusticum and thence apparently spread diffusely through the cerebellum. Cutting the lateral-line nerve on one side silences the ipsilateral tuberculum acusticum, but only reduces the intensity of ipsilateral cerebellar activity. Cutting the remaining lateral-line nerve silences activity throughout the tuberculum acusticum and the cerebellum.

The maintenance of tonic activity in the tuberculum acusticum by way of lateral-line discharge may account for the inhibitory effects of the lateral-line system on auditory responses.
THE EXTINCTION OF REFLEXES IN SPINAL MICE OF DIFFERENT AGES AS AN INDICATOR OF THE DECLINE OF ANAEROBIOSIS
Authors: Enzmann E. V. , Pincus G.
Published: May 2004

In spinal mice the latent period between decapitation and the disappearance of all spinal reflexes decreases regularly with increasing age (Fig. 1). Available evidence indicates that this latent period may be proportional to the capacity for anaerobic metabolism at various ages.
TEMPERATURE CHARACTERISTICS FOR THE METABOLISM OF CHLORELLA
Authors: French C. S.
Published: May 2004

The decomposition of hydrogen peroxide by intact Chlorella cells follows a first order course at very low temperatures, but at higher temperatures gives falling first order constants. Between 0.6° and 20°C. the value of µ is 10,500 calories.
RESULTS OF IRRADIATING SACCHAROMYCES WITH MONOCHROMATIC ULTRA-VIOLET LIGHT
Authors: Oster Robert H.
Published: May 2004

Possible variation in the probability that absorbed quanta of ultra-violet energy will produce observable inhibitory and lethal effects in the yeast cell, due to non-uniformity in sensitivity of the different regions of the cell, may be further modified by the reproductive stage of the cell at the time of irradiation. Tests of the survival of yeast cells of 15 day and 24 hour cultures indicate that the older resting cells are more resistant to ultra-violet irradiation effects than cells undergoing rapid cell division.

The effects of temperature changes within the range of normal growth are evidently small, as judged from the temperature coefficient (1.10).

Possible inhibitory effects due to the action of ultra-violet radiation on the malt agar medium and to toxic substances diffused from cells killed by irradiation were not found under the conditions of the experiments.

Tests of the validity of the Bunsen-Roscoe reciprocity law for variation in the intensity of the incident ultra-violet radiation up to 30 per cent indicate that for this range the rate of absorption of quanta by the cell does not produce any marked change in the lethal effects observed.
THE ABSORPTION OF ULTRA-VIOLET RADIATION BY CRYSTALLINE PEPSIN
Authors: Gates Frederick L.
Published: May 2004

Determination of the absorption spectra of pure preparations of Northrop's crystalline pepsin inactivated by irradiation with ultra-violet light shows that the total absorption in the ultra-violet region of the spectrum increases with the degree of inactivation. This increase is especially marked between 2400 and 2750 Å.u. The rate of photoinactivation is shown to be sensitive to changes in pH, increasing with lower values, and evidently bears a one-quantum relationship to the energy flux. Tests of the rate of inactivation of pepsin exposed to several different bands of the ultra-violet spectrum, in relation to the absorbed energy, indicate that the destruction spectrum of the enzyme agrees essentially with its absorption spectrum and is similar to that of urease.
THE ACCUMULATION OF ELECTROLYTES
Authors: Jacques A. G.
Published: May 2004

Analyses have been made of the inorganic constituents of the juices expressed from the leaves of Rheum, Rumex, and Oxalis.

It has been shown that in all cases there is a large excess of inorganic cations over anions in the sap, the average ratio of cations to anions being 3.8 (Part 1, p. 239).

The ash analyses of plant tissues (chiefly leaves) reported in the literature have been examined critically, and it has been shown that the preponderance of inorganic cations over inorganic anions in the ash and in the sap is general.

It has been concluded that the excess of inorganic cations is consistent with the view that cations pass into the protoplasm chiefly in the form of hydroxides, and are accumulated either in the form of organic salts (such as the oxalates) or in non-polar linkage.

It has been concluded that practically all the potassium and sodium found in plant ash must have been present originally in the form of soluble ionogenic compounds, but that a considerable part of the calcium and magnesium may have been present originally in the form of insoluble salts or as components of non-polar compounds.

The methods whereby the cations, particularly potassium, may have been accumulated have been discussed, and it has been concluded that as it does not seem very probable that they enter chiefly as nitrates or bicarbonates we may suppose that they go in to a large extent as hydrates: this is highly probable in the case which has been most carefully investigated (Valonia).
SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS
Authors: Mirsky A. E. , Anson M. L.
Published: May 2004

1. Methods have been described for reducing protein S-S groups, for oxidizing protein SH groups, and for estimating protein S-S and SH groups.

2. It has been found necessary in estimating the cystine content of proteins by the Folin-Marenzi method to take into account any cysteine that may be present.

3. A method for estimating the cysteine content of proteins has been described.

4. With these methods, estimations have been made of the S-S and SH groups and of the cystine and cysteine contents of a number of proteins.

5. In a denatured, but unhydrolyzed protein, the number of S-S and SH groups is equivalent to the quantity of cystine and cysteine found in the protein after hydrolysis.
PRODUCTS OF THE OXIDATION OF THIOSULFATE BY BACTERIA IN MINERAL MEDIA
Authors: Starkey Robert L.
Published: May 2004

Various cultures (previously described), which oxidize thiosulfate in mineral media have been studied in an attempt to determine the products of oxidation. The transformation of sodium thiosulfate by Cultures B, T, and K yields sodium tetrathionate and sodium hydroxide; secondary chemical reactions result in the accumulation of some tri- and pentathionates, sulfate, and elemental sulfur. As a result of the initial reaction, the pH increases; the secondary reactions cause a drop in pH after this initial rise. The primary reaction yields much less energy than the reactions effected by autotrophic bacteria. No significant amounts of assimilated organic carbon were detected in media supporting representatives of these cultures. It is concluded that they are heterotrophic bacteria.

Th. novellus oxidizes sodium thiosulfate to sodium sulfate and sulfuric acid; the pH drops progressively with growth and oxidation. Carbon assimilation typical of autotrophic bacteria was detected; the ratio of sulfate-sulfur formed to carbon assimilated was 56:1. It is calculated that 5.1 per cent of the energy yielded by the oxidation of thiosulfate is accounted for in the organic cell substance synthesized from inorganic materials. This organism is a facultative autotroph.

The products of oxidation of sodium thiosulfate by Th. thioparus are sodium sulfate, sulfuric acid, and elemental sulfur; the ratio of sulfate sulfur to elemental sulfur is 3 to 2. The pH decreases during growth and oxidation. The elemental sulfur is produced by the primary reaction and is not a product of secondary chemical changes. The bacterium synthesizes organic compounds from mineral substances during growth. The ratio of thiosulfate-sulfur oxidized to carbon assimilated was 125:1, with 4.7 per cent of the energy of oxidation recovered as organic cell substance. This bacterium is a strict autotroph.
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Osterhout W. J. V. , Hill S. E.
Published: May 2004

Several forms of the action curve are described which might be accounted for on the ground that the outer protoplasmic surface shows no rapid electrical change. This may be due to the fact that the longitudinal flow of the outgoing current of action is in the protoplasm instead of in the cellulose wall. Hence the action curve has a short period with a single peak which does not reach zero.

On this basis we can estimate the P.D. across the inner and outer protoplasmic surfaces separately. These P.D.'s can vary independently.

In many cases there are successive action currents with incomplete recovery (with an increase or decrease or no change of magnitude).

Some of the records resemble those obtained with nerve (including bursts of action currents and after-positivity).
A COMPARISON OF THE ELECTROPHORETIC VELOCITIES OF CELLOPHANE AND COLLODION SUSPENSIONS WITH ELECTROOSMOTIC VELOCITIES THROUGH MEMBRANES OF THE SAME MATERIALS
Authors: Monaghan Betty , White H. L. , Urban Frank
Published: May 2004

It is demonstrated that the isoelectric concentration of ThCl4 is much greater for electroosmosis in small-pored membranes (cellophane, collodion) than for electrophoresis of particles of the same material. An explanation for the difference is advanced, based on the influence of the small pores in preventing complete development of the electrical double layer.
STUDIES ON BLOOD COAGULATION
Authors: Eagle Harry
Published: May 2004

Although calcium is essential for the formation of thrombin, it can be recovered quantitatively from formed horse thrombin without affecting its coagulating activity. Citrate also has no significant effect. As stated in the text, this does not exclude the possibility that thrombin is actually a calcium compound present in minute concentration; but confirming the results of Hammarsten, it does show that fibrin cannot be a calcium-protein compound unless one assumes molecular weights for fibrinogen greater than 1,000,000.

Although the available experimental data concerning the properties of thrombin, the kinetics of its reaction with fibrinogen, and the quantitative relationships between the two do not allow a definite decision as to whether thrombin is an enzyme analogous to rennin, or whether it combines with fibrinogen to form an insoluble compound, fibrin, the weight of evidence does favor the enzyme theory. A given quantity of thrombin can form at least 200 times its weight of fibrin, and in view of the crudeness of the preparation this ratio is probably many times greater. There is no apparent stoichiometric relationship between thrombin and fibrinogen, and thrombin does not disappear from a mixture of the two until the moment of coagulation; the quantity which then disappears is many times the minimal quantity necessary to form the amount of fibrin produced.
A PARADOXICAL RELATION BETWEEN ZETA POTENTIAL AND SUSPENSION STABILITY IN S AND R VARIANTS OF INTESTINAL BACTERIA
Authors: Joffe Eleanore W. , Mudd Stuart
Published: May 2004

The relation between electrokinetic potential and suspension stability of four strains of non-flagellate intestinal bacteria has been studied. The smooth forms have ζ-potentials which approximate zero over a wide range of pH and salt concentration, yet nevertheless form stable suspensions. The rough variants have ζ-potentials which vary with pH and electrolyte concentration in the familiar way. The rough forms have values of ζ-potential critical for their suspension stability.
THERMAL RECEPTION IN FISHES
Authors: Rubin Morton A.
Published: May 2004

The reactions of catfish, sunfish, perch, and mummichog to temperature changes, as described in this paper, indicate that certain receptors supplied by the lateral-line nerve are concerned with thermal reception.
STUDIES ON THE ELIMINATION OF DYES IN THE GASTRIC AND PANCREATIC SECRETIONS, AND INFERENCES THEREFROM CONCERNING THE MECHANISMS OF SECRETION OF ACID AND BASE
Authors: Ingraham Raymond C. , Visscher Maurice B.
Published: May 2004

1. All dyes appearing in gastric juice after intravenous injection in the dog are characterized by having their chromogen in the electropositive ion under suitable conditions.

2. All dyes eliminated in pancreatic juice ionize with the chromogen electronegative under proper circumstances.

3. The amphoteric characteristics of certain dyestuffs, as well as the changes in charge associated with reversible reduction in others, have been taken into consideration, and the lack of success of previous investigators in finding a common characteristic of dyes secreted by the gastric glands differentiating them from those secreted by the pancreas, has been shown to have been due to failure to take these potentialities of the dyestuffs into account.

4. Several possible hypotheses concerning the mechanism of selectivity to dyestuffs have been considered. Differences in distribution in acid, neutral, and alkaline phases will not account for selective secretion without postulating also specific membrane permeability. It is pointed out that the theory most thoroughly in accord with all the facts observed is based upon the pore concept. To restrain electronegative dyes by polar adsorption, the pores of the membranes of the gastric glands would have to be positively charged. Such pores would constitute an electrostatic filter, restraining from passage all mobile ions of the same charge. The anions, which in plasma are mostly chloride, could pass this barrier into the secretion. In order to have hydrochloric acid formation, anion exchange would have to occur, bicarbonate, lactate, or some other anion from the gland lumen returning to balance chloride entering, leaving the hydrogen ion from the weaker acid in the secretion. This tentative theory can also be seen to fit many of the facts of pancreatic secretion, where electropositive dyes are restrained, and alkali is secreted.
CORRELATION OF OXIDATION AND PHOSPHORYLATION IN HEMOLYZED BLOOD IN PRESENCE OF METHYLENE BLUE AND PYOCYANINE
Authors: Runnström John , Michaelis Leonor
Published: May 2004

1. The system:hemolyzed blood + glucose never exhibits glycolysis or, in the air, oxidation of glucose. When glucose is replaced by hexosephosphate ester, addition of methylene blue causes oxidation in air.

2. When cozymase is added also, the oxidation is increased, and a synthesis of hexosephosphate esters takes place.

3. When pyocyanine is used instead of methylene blue, the rate of oxidation is the same as with methylene blue, but a synthesis of phosphate esters takes place without addition of cozymase.

4. There is never a phosphate ester synthesis without oxidation going on, but oxidation does not necessarily go hand in hand with phosphate synthesis.

5. In order to couple the oxidation process with phosphate synthesis, two methods are available: either to start oxidation by methylene blue and to add coenzyme from yeast cells; or to start oxidation by pyocyanine, in which case coenzyme is unnecessary, though it improves the effect.

6. Iodoacetate always suppresses synthesis, but only under certain conditions decreases oxidation. Cyanide has no effect upon either process.
ORIENTATION BY OPPOSED BEAMS OF LIGHT
Authors: Crozier W. J. , Kropp Benjamin
Published: May 2004

Computations of the effective angular inclination (H) of the photoreceptive surfaces of the two sides, based upon measurements of orientation angles under the action of beams of light directly opposed or crossing at right angles, show that with larvae of Calliphora and of Lucillia H declines as the total illumination decreases (i.e., as the angle of orientation away from the more intense light increases). H is greater with the two lights opposed at 180°; this may be due to the difference in refraction. For the more sharply pointed larvae of Lucillia, H is less than half as great as in Calliphora.
RELATION BETWEEN BIRTH WEIGHT AND LITTER SIZE IN MULTIPAROUS MAMMALS
Authors: Enzmann E. V. , Crozier W. J.
Published: May 2004

In multiparous mammals there is a definite relation between the litter size N and the total weight of the litter W. Reasons are given showing that this relationship is independent of the mechanism of parturition.

For various forms W = NK + const. Hence the average increment of W due to unit increase of N is directly proportional to W, inversely to N. This signifies proportionality between N and nutritive drain upon the mother, as well as equipartition among the members of the litter. K is non-specific, and is therefore regarded as a partition index.
STUDIES ON BLOOD COAGULATION
Authors: Eagle Harry , Baumberger J. P.
Published: May 2004

The coagulation of fibrinogen by thrombin does not involve a significant shift in the hydrogen ion concentration of the free fluid.
THE SOLUBILITIES, APPARENT DISSOCIATION CONSTANTS, AND THERMODYNAMIC DATA OF THE DIHALOGENATED TYROSINE COMPOUNDS
Authors: Winnek Philip S. , Schmidt Carl L. A.
Published: May 2004

1. The solubilities and differential heats of solution of d-tyrosine, dl-tyrosine, diiodo-dl-tyrosine, dibromo-l-tyrosine (hydrated), dibromo-l-tyrosine (anhydrous), and dichloro-l-tyrosine (hydrated) have been determined.

2. Evidence has been advanced that dl-tyrosine is a compound.

3. From the solubility determinations at various acidities, the apparent acid and basic dissociation constants of dibromo-l-tyrosine and dichloro-l-tyrosine have been determined at 25° and 40°C. From these data the apparent heats of ionization have been calculated.

4. The question concerning which of the groups in l-tyrosine and its dihalogenated substitution products is responsible for each dissociation constant has been discussed.
THE ELECTRICAL ACTIVATION OF PASSIVE IRON WIRES IN NITRIC ACID
Authors: Lillie Ralph S.
Published: May 2004

1. The relation between the E. M. F. and the minimal duration of an activating current has been determined for passive iron wires in nitric acid under varying conditions of concentration of acid, duration of recovery period, and presence of surface-action compounds.

2. The characteristic intensity-duration curves resemble those of irritable living tissues with moderate speeds of response to stimulation (with chronaxies of the order of 10 to 30σ).

3. The intensity of the current required for activation, as well as its minimal effective duration for a given intensity, increases rapidly with increase in the concentration of HNO3.

4. The responsiveness of the iron wire to brief currents is low immediately after activation and returns progressively to the original level during the immediately following period, at first rapidly and then slowly, following a time curve resembling the corresponding curve of living tissues during the relative refractory period.

5. Surface-active compounds decrease reversibly, to a degree dependent on concentration, the responsiveness of iron wires to brief currents.

6. Conditions are described under which the iron wire is activated by the break of an already flowing constant current.
THE EFFECT OF X-RAYS ON CHROMOSOMES IN DIFFERENT STAGES OF MEIOSIS
Authors: Marshak A.
Published: May 2004

1. Pollen mother cells exposed to low dosages of x-rays at various stages show different frequencies of chromosome abnormalities in the first meiotic anaphase.

2. Maximum frequencies of abnormalities were obtained in buds irradiated in the pachytene stage of the meiotic prophase and in the preceding mitosis.

3. These results are taken to indicate that the x-ray-sensitive portions of the chromonemata are closely approximated in pairs in pachytene and in the early mitotic prophase. The significance of this in relation to non-homologous pairing is indicated.

4. From the nature of the chromosome configurations observed it is concluded that chromonemata are two-parted when they synapse and that a chromonematic division occurs between pachytene and anaphase and during the mitotic prophase.

5. The frequencies of abnormalities show a linear relationship to dosage.

6. The diameter of the sensitive volume of the chromonema is calculated and found to approximate the diameter of some known protein molecules.

7. The linkage mechanism is found to make up about 90 per cent of the total sensitive volume which corresponds with the approximate reduction in length of the chromonema from pachytene to anaphase.

8. The relation of these sensitive volumes to the gene is discussed.
ACTION POTENTIALS IN THE NERVOUS SYSTEM OF THE CRAYFISH
Authors: Prosser C. Ladd
Published: May 2004

Increase in temperature elicits an increase in the number of nerve impulses arising spontaneously from deafferented crayfish ganglia. This alteration in gross frequency gives an apparent temperature characteristic of 27,000 calories.

Changes in the number of active fibers and in the frequency of discharge of individual units account for the alterations in the gross frequency. The change in number of active units gives a n value of 17,500 calories.

Individual fibers fall into two groups with respect to the effect of temperature on their frequency of discharge. One of these groups exhibits a µ value of 14,500 calories and the other yields a µ value of 7,000 calories.
ADAPTATION OF CUTANEOUS TACTILE RECEPTORS. III
Authors: Hoagland Hudson
Published: May 2004

Further experimental evidence is presented indicating that the peripheral inhibitory phenomenon known as sensory adaptation, as it is manifested in tactile receptors in frogs' skin, is produced by a neurohumor released by non-nervous cells of the skin when they are pressed upon.

1. Adaptation is not produced by electrically initiated antidromic impulses backfired into the axon branches.

2. Intermittent air jet stimulation of a region of skin several millimeters distant from a responsive single ending produces failure of response of the ending to a similar direct intermittent stimulus applied to the skin containing the ending immediately afterward.

3. Constant pressure causes an ending to adapt but no spread of the effect, as described in the above paragraph, is found. This implies that the spread is the result of the vibratory movement of the skin.

4. The time curves of recovery from adaptation are inconsistent with any known properties of isolated nerve.
PACEMAKERS IN NITELLA
Authors: Hill S. E. , Osterhout W. J. V.
Published: May 2004

A series of negative variations passing along the cell may reach a region where only every other variation registers. This condition may be temporary. It would seem to depend on a local change in the refractory period.
THE DARK ADAPTATION OF RETINAL FIELDS OF DIFFERENT SIZE AND LOCATION
Authors: Hecht Selig , Haig Charles , Wald George
Published: May 2004

The decrease in threshold shown by the eye during dark adaptation proceeds in two steps. The first is rapid, short in duration, and small in extent. The second is slow, prolonged, and large. The first is probably due to cone function; the second to rod function.

In centrally located fields the two parts of adaptation change differently with area. With small, foveal fields the first part dominates and only traces of the second part appear. As the area increases the first part changes a little, while the second part covers an increasing range of intensities and appears sooner in time.

Measurements with an annulus field covering only the circumference of a 20° circle show most of the characteristics of a 20° whole field centrally located. Similarly a 2° field located at different distances from the center shows dark adaptation characteristics essentially like those of large centrally located fields whose edges correspond to the position of the central field.

Evidently the behavior in dark adaptation of centrally located fields of different size is determined in the main not by area as area, but by the fact that the retina gradually changes in sensitivity from center to periphery, and therefore the larger the field the farther it reaches into peripheral regions of permanently greater sensibility.
RELATION OF OXYGEN TENSION AND TEMPERATURE TO THE TIME OF REDUCTION OF CYTOCHROME
Authors: Stier T. J. B.
Published: May 2004

The time for the appearance of the cytochrome C absorption band after shaking a suspension of bakers' yeast with various O2-N2 mixtures was determined at each of six temperatures. At each temperature a linear relation between this interval—called the reduction time—and O2 tension was found. It was shown:

1. That under our experimental conditions, absorption bands of cytochrome were seen when the O2 tension of the suspension was reduced to, or below, a certain pressure which was found to be specific for each temperature (this pressure is provisionally considered to be identical with or very near to the "critical O2 tension" usually found in QOO2-O2-tension relationships);

2. That the x-axis intercept obtained from the reduction time - O2-tension plot gives the value of the "critical" O2 pressure at each temperature;

3. That the O2 tension within the suspension is reduced by the respiratory activity of the yeast cells.

An equation describing these observations is given and is used in calculating rates of O2 consumption from measurements of reduction time of cytochrome. The average difference between the calculated values and the manometric measurements of QOO2 was found to be 6.6 per cent. A rapid optical method of measuring rates of O2 consumption based on the findings of these experiments is proposed for use with cytochrome-containing microorganisms.
CAROTENOIDS AND THE VISUAL CYCLE
Authors: Wald George
Published: May 2004

1. Carotenoids have been identified and their quantities measured in the eyes of several frog species. The combined pigment epithelium and choroid layer of an R. pipiens or esculenta eye contain about 1γ of xanthophyll and about 4γ of vitamin A. During light adaptation the xanthophyll content falls 10 to 20 per cent.

2. Light adapted retinas contain about 0.2–0.3 γ of vitamin A alone.

3. Dark adapted retinas contain only a trace of vitamin A. The destruction of their visual purple with chloroform liberates a hitherto undescribed carotenoid, retinene. The bleaching of visual purple to visual yellow by light also liberates retinene. Free retinene is removed from the isolated retina by two thermal processes: reversion to visual purple and decomposition to colorless products, including vitamin A. This is the source of the vitamin A of the light adapted retina.

4. Isolated retinas which have been bleached and allowed to fade completely contain several times as much vitamin A as retinas from light adapted animals. The visual purple system therefore expends vitamin A and is dependent upon the diet for its replacement.

5. Visual purple behaves as a conjugated protein in which retinene is the prosthetic group.

6. Vitamin A is the precursor of visual purple as well as the product of its decomposition. The visual processes therefore constitute a cycle.
THE IMMUNOLOGICAL SPECIFICITY OF THE EUGLOBULIN AND PSEUDOGLOBULIN FRACTIONS OF HORSE AND H^MAN SERUM
Authors: Harris Tzvee , Eagle Harry
Published: May 2004

That portion of horse and human serum globulin precipitated by 33 per cent saturation with ammonium sulfate and precipitated on subsequent dialysis was taken as euglobulin; and the fraction precipitated between 33 and 50 per cent saturation and remaining in solution on subsequent dialysis was taken as pseudoglobulin.

The sera of rabbits injected with either of these antigens gave precipitation with both. However, two distinct and fraction-specific antibodies could be demonstrated by absorbing the sera with the one antigen, and testing the supernatant fluid with the other. The experimental results are adequately explained on the basis that there are at least two antigenically distinct globulins in serum which we may term globulin I and globulin II and which are largely associated with so called euglobulin and pseudoglobulin respectively. The ordinary methods of salting out and dialysis do not effect complete separation and each globulin preparation contains a trace of the other antigen. The antisera to these euglobulin and pseudoglobulin preparations therefore contain antibodies to both antigens. Each protein solution precipitates all the antibody specific for the one antigen and in addition, by virtue of the trace of contaminating protein, precipitates a portion, and only a portion of the antibody specific for the other antigen.

The fact that antisera to whole serum contain these same fraction-specific antibodies suggests that this immunological specificity is an inherent property of two globulins present as such in serum and is not an artifact induced by their precipitation and purification.

Lipoids extracted from the globulins by ether, petroleum ether, and alcohol give no demonstrable reaction with antisera to these globulins; antisera absorbed with a large excess of lipoid are not affected as regards their reactivity with the original protein; and globulins extracted with ether and petroleum ether at room temperature are not affected as regards their reactivity with antisera. It is concluded that the immunological specificity of the globulin fractions as evidenced by the precipitation reaction is not determined by lipoids associated with the protein.
SULFHYDRYL AND DISULFIDE GROUPS OF PROTEINS
Authors: Mirsky A. E. , Anson M. L.
Published: May 2004

Hemoglobin and the proteins of the crystalline lens contain active SH groups while in the native state, the number of active groups increasing as the pH rises. All the SH groups of denatured globin and of the denatured lens proteins are active at a pH so low that practically none of the SH groups of native hemoglobin and of native lens protein are active. The effect of denaturation on the SH groups of a protein is to extend towards the acid side the pH range of their activity.

It is possible to oxidize the iron-porphyrin and the SH groups of hemoglobin independently of each other.
THE REDUCING GROUPS OF PROTEINS
Authors: Mirsky A. E. , Anson M. L.
Published: May 2004

1. Intact, unhydrolyzed proteins possess in addition to SH groups other reducing groups which can be oxidized by ferricyanide.

2. The activity of these reducing groups, like that of SH groups, is enhanced by denaturation of the protein and by increase of pH and temperature.

3. These groups differ from SH groups in the manner in which their activity is dependent on concentration of ferricyanide and time of contact with ferricyanide.

4. The activity of these groups is increased if protein SH groups are present.

5. The number and activity of these groups varies from protein to protein.

6. These groups are probably contained in the tyrosine and tryptophane components of proteins.

7. The significance of these reducing groups for an understanding of protein denaturation and the reducing properties of tissues is indicated.
A KINETIC ANALYSIS OF THE ENDOGENOUS RESPIRATION OF BAKERS' YEAST
Authors: Stier T. J. B. , Stannard J. N.
Published: May 2004

The process of endogenous respiration of two strains of bakers' yeast, Saccharomyces cerevisiae, was examined kinetically. The rate of respiration with respect to time in a non-nutrient medium was found to exhibit two phases: (a) a period of constant rate of O2 consumption and CO2 production (R.Q. = 1) characteristic of cells with ample concentrations of stored material; (b) a first order decline in rate of respiration with respect to time, where the rate was proportional to the concentration of some substrate, S. (R.Q. = 1 throughout second phase.) The nature of this substrate was reexamined and the evidence summarized confirms the notion that it is a carbohydrate, probably glycogen. These phases of endogenous respiration were shown to depend upon the age of the culture and the amount of substrate available.
THE METABOLIC SYSTEMS INVOLVED IN DISSIMILATION OF CARBOHYDRATE RESERVES IN BAKERS' YEAST
Authors: Stier T. J. B. , Stannard J. N.
Published: May 2004

Evidence is presented showing that the dissimilation of carbohydrate reserves in two strains of bakers' yeast, Saccharomyces cerevisiae, is a purely respiratory process.

Endogenous respiration is KCN-labile. Our own experiments together with various accounts and data given in the literature show that the same "oxygen-transporting mechanism" functions in both endogenous and exogenous metabolism. However, the lack of sensitivity of the endogenous system of reactions to low concentrations of monoiodoacetic acid, the absence of anaerobic CO2 production, and the absence of alcohol production, demonstrate that fermentation is not involved in the dissimilation of the carbohydrate reserves.

Throughout the experiments the endogenous respiration behaved functionally as a unitary system of reactions. The O2 consumption and CO2 production were parallel at all times; i.e., the R. Q. was consistently 1. Monoiodoacetic acid and KCN in concentrations from 10–5 to 10–1 molar affected both O2 uptake and CO2 production to the same extent. The only agents known to alter the value of the R. Q. were those which disrupted the normal protoplasmic structure, viz. grinding the cells with sand, plasmolyzing them with toluol and hypertonic salt solutions, or pressing them in a hydraulic press. These agents brought about a vigorous anaerobic CO2 production accompanied by an accumulation of alcohol in the medium.

The unitary character of endogenous respiration is exhibited only when the normal structure of the cell is kept intact; apparently it depends upon the maintenance of a chambered (or compartmental) architecture of the cell.
ON THE VARIABILITY OF CRITICAL ILLUMINATION FOR FLICKER FUSION AND INTENSITY DISCRIMINATION
Authors: Crozier W. J.
Published: May 2004

From the data of experiments with bees in which threshold response is employed as a means of recognizing visual discrimination between stripes of equal width alternately illuminated by intensities I1 and I2, it is shown that the detectable increment of intensity ΔI, where ΔI = I2 - I1, is directly proportional to σI2 (I1 being fixed). From tests of visual acuity, where I1 = 0 and the width of the stripes is varied, σI2 = kI2 + const.; here I2 = ΔI, and ΔI/I2 = 1. When the visual excitability of the bee is changed by dark adaptation, λI ≡ kΔI (= k' σΔI) = k'' I + const. For the measurements of critical illumination at threshold response to flicker, σI2 (= σΔI) = k I2 = k' ΔI + const.

The data for critical illumination producing threshold response to flicker in the sun-fish Lepomis show for the rods σI2 = K I2 for the cones σI2 = K'(I2 + const.).

The data thus indicate that in all these experiments essentially the same visual function is being examined, and that the recognition of the production of a difference in effect by alternately illuminated stripes takes place in such a way that d (ΔI)/d (σI2) = const., and that ΔI is directly proportional to I (or "I2," depending on the nature of the experiment).

It is pointed out that the curve for each of the cases considered can be gotten equally well if mean I or σI is plotted as a function of the independent variable involved in the experiment.

Certain consequences of these and related facts are important for the treatment of the general problem of intensity discrimination.
THE CHANGE IN STATE OF THE PROTEINS OF MUSCLE IN RIGOR
Authors: Mirsky A. E.
Published: May 2004

1. When myosin is exposed to a typical denaturing agent (acid) it becomes insoluble and its SH groups are activated.

2. The same number of active SH groups is found in the soluble myosin of resting muscle as in the insoluble myosin of muscle in rigor. No activation of SH groups accompanies the formation of insoluble protein in rigor.

3. When the insoluble myosin of muscle in rigor is treated with a denaturing agent its SH groups are activated.

4. Protein coagulation as brought about by denaturing agents (heat, acid, alkali, alcohol, urea, salicylate, surface forces, ultraviolet light) is a distinctly different change from the coagulation of myosin brought about by the unknown agent in muscle.
THE ELECTRICAL CHARGE OF MAMMALIAN RED BLOOD CELLS
Authors: Abramson Harold A. , Moyer Laurence S.
Published: May 2004

From data on the surface area and electrical mobilities of mammalian red blood cells in M/15 phosphate buffer at pH 7.4, it has been possible, with the help of the Gouy and von Smoluchowski theories, to calculate the net surface charge per cell as well as the charge per unit area. It was found that a single mammalian red cell has a net surface charge ranging from four to fifteen million electrons, depending on the species. No clear relationship between zoological classification and surface charge is apparent. It is suggested that a mechanism exists which is capable of keeping the surface density of net charge constant when comparatively large changes in surface area occur in the anemias.
STIMULATION OF FUNDULUS BY OXALIC AND MALONIC ACIDS AND BREATHING RHYTHM AS FUNCTIONS OF TEMPERATURE
Authors: Sizer Irwin W.
Published: May 2004

1. Chemical stimulation as a function of temperature was studied by using oxalic acid in fresh and salt water and malonic acid in salt water as stimulating agents on Fundulus. According to the Arrhenius equation the following µ values were obtained for the various acid solutions between 0 and 29°C.: for 0.002N oxalic in fresh water—15,800; 33,000; for 0.0008N oxalic in fresh water—15,800; 33,000; 48,000; for 0.002N oxalic in salt water—19,400; 24,100; 56,500; for 0.004N and 0.002N malonic in salt water—20,600; 65,000. At a critical temperature there is a sharp transition from one thermal increment to another.

2. The chemical processes controlling stimulation do not change with concentration, for different normalities of a single acid yield the same µ values. Distinctly different temperature characteristics were obtained for stimulation by oxalic in salt and fresh water. Likewise stimulation by oxalic and malonic in salt water yielded very different increments. This temperature study indicates that the controlling chemical reactions determining rate of response are different for the same acid in two different environments, or for two dibasic acids in the same environment. Other work indicates, however, that the fundamental stimulation system is the same for all the adds in both environments. Chemical rather than physical processes limit the rate of response since all the values are above 15,000. Stimulation depends upon a series of interrelated chemical reactions, each with its own temperature characteristic. Under varying conditions (e.g. change of temperature, environment, or acid) different chemical reactions may become the slowest or controlling process which determines the rate of response.

3. The variation of response, as measured by the probable error of the mean response time of the fish, is the same function of temperature as reaction time itself. Hence variability is not independent of reaction time and is controlled by the same catenary series of events which determine rate of response to stimulation.

4. Breathing rhythm of Fundulus as related to temperature was studied in both salt and fresh water. In salt water the temperature characteristic is 8,400 while in fresh water it is 16,400 below 9.5°C., and 11,300 above this critical temperature. These µ values are typical of those which have been reported by other workers for respiratory and oxidative biological phenomena. A change in thermal increment with an alteration in environment indicates that different chemical reactions with characteristic velocity constants are controlling the breathing rhythm in salt and fresh water.
EFFECT OF PROTEINS ON ELECTROPHORETIC MOBILITY AND SEDIMENTATION VELOCITY OF RED CELLS
Authors: Monaghan B. R. , White H. L.
Published: May 2004

The isoelectric point of normal red cells cannot be measured but is certainly lower than that of any plasma protein. Red cells are easily damaged so that they will adsorb proteins from low concentrations. Normal red cells do not adsorb protein even from concentrated solutions, as is evidenced by the finding that the ratio of the mobility of the cells to that of the proteins themselves is at least as high in concentrated casein, albumin, gelatin, or fibrinogen solutions as in dilute.

The finding that the observed mobility of red cells is unchanged or only slightly decreased when bulk viscosity is increased by added protein is interpreted as indicating that the red cell surfaces are hydrated. The aggregating effect of certain proteins has been determined and is assumed to be due to their dehydrating effect on the cells. Some types of cells, as beef, are not aggregated, presumably because they are resistant to this dehydrating effect. The difference in the behavior of different types of red cells demonstrates the importance of the nature of the cell as well as of the medium in determining the rate of aggregation and therefore of sedimentation.