bluuebunny/crossref_metadata_2025 huggingface dataset:
THEORY AND MEASUREMENT OF VISUAL MECHANISMS
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

The relation between flash duration and mean critical intensity (white light) for threshold recognition of visual flicker, as a function of flash frequency, was investigated by means of measurements at five values of the light-time fraction: 0.10, 0.25, 0.50, 0.75, 0.90, with flash frequencies of the interrupted beam ranging from 2 to 60 per second. A square area, 6.1 x 6.1°, centrally fixated) was viewed monocularly; the discriminometer used provides automatically an artificial pupil 1.8 mm. in diameter. Except for the slight day-to-day fluctuation in the magnitudes of the parameters, the data for the observer used are shown to form an essentially homogeneous group.

As for other animals tested, the F - log Im curve is enlarged and moved toward lower flash intensities as the light-time fraction is decreased. The high intensity segments of the duplex curves are fitted by normal probability integrals for which F max. and the abscissa of inflection are rectilinear functions of tL(tL + tD), with opposite slopes. The third parameter, (σ'log I, is invariant.

The low intensity segments are composites, their shapes determined by the summation of the lower part of the high intensity curve with an overlapping low intensity population of effects. Both the rising and the declining branches of this latter assemblage suffer competitive partial suppression by the effects in the high intensity population. The detailed analysis shows that these results are consistent with the theory of the central, rather than peripheral, location of the dynamically recognizable elements in the determination of flicker.
STUDIES IN THE PHYSIOLOGY OF FUSARIA. THE RESPIRATORY AND FERMENTATIVE MECHANISMS
Authors: Gould Bernard S. , Tytell Alfred A.
Published: May 2004

1.Fusarium tricothecoides was selected for a study of the respiratory and fermentative activities of Fusaria. "Resting cell" suspensions were investigated by the Barcroft manometric technique.

2. The results of the investigation indicate clearly that the mechanism of endogenous metabolism (respiration) is distinct from the exogenous mechanism (fermentation). Anaerobically no significant CO2 production is apparent without added substrate. In the presence of glucose the anaerobic CO2 evolution is practically equal to the added CO2 evolved aerobically in the presence of added glucose.

Low concentrations of iodoacetate or fluoride selectively poison the exogenous mechanism but do not affect the endogenous mechanism.

Alcohol is not produced in the course of endogenous metabolism, but is produced in the presence of added glucose.

3. A study of the metabolism of the organism throughout its entire growth phase from 1 to 7 days has been made.

4. The ability of suspensions of Fusarium sp. H., obtained by growth on a variety of common substrates, to attack a large number of carbon sources with the production of exogenous CO2 was determined. It is found that organisms grown on glucose will attack only glucose, mannose, and fructose, but none of the common intermediary metabolites except pyruvic acid. Organisms grown on galactose attack galactose, as well as the other hexoses, indicating an adaptive mechanism.

5. An identical mechanism for the dissimilation of glucose, mannose, and galactose is indicated since no additive effects with these substrates were observed. Growths on non-hexose carbon sources attack glucose slightly under the experimental conditions with the evolution of CO2, but do not attack any other substrate. This would indicate a residual glucose-dissimilating mechanism in all growths investigated.

6. Striking similarities between the general metabolism of resting suspensions of Fusarium sp. H. and resting suspensions of yeast cells are apparent.
ANAEROBIC GLYCOGENOLYSIS IN THE MUSCLES OF RANA PIPIENS LIVING AT LOW TEMPERATURES
Authors: Barger A. N. , Johnson R. E.
Published: May 2004

1. A considerable proportion of R. pipiens caught in the spring and stored without food for several weeks at about 4°C. had gastrocnemii that did not break down glycogen when they contracted anaerobically to complete exhaustion. A smaller number of the same muscles did not produce lactate.

2. There was no evident relation between failure to break down glycogen and the glycogen content of such muscles, some of which had more than 500 mg. of glycogen per 100 gm. of tissue.

3. The hypothesis of Meyerhof and his followers that aerobic contraction of frog muscles may at times take place with sources of energy other than carbohydrate is therefore extended to include anaerobic contraction.
THE EFFECT OF SONIC VIBRATIONS ON PHAGE, PHAGE PRECURSOR, AND THE BACTERIAL SUBSTRATE
Authors: Krueger A. P. , Brown B. B. , Scribner E. J.
Published: May 2004

1. A nickel tube magneto-striction oscillator of 320 watts output producing sonic vibrations of 9,300 cycles per second frequency is described. Certain structural innovations contribute to operating efficiency and permit more convenient exposure of test materials than in earlier types.

2. The rate of phage inactivation by sonic waves proceeds logarithmically with time and serves as a satisfactory measure of energy output during operation of the generator. The curve for phage inactivation taking place in the presence of homologous staphylococci follows that for phage alone but soon reaches a plateau after which no further loss of activity is noted. In general higher concentrations of bacteria more effectively inhibit phage destruction than do lower concentrations.

3. Cells that have attained a resting state after a preliminary phase of rapid growth normally have the capacity of inducing a very rapid and marked increase in [phage] when added to phage. This effect has been attributed to the presence of intracellular phage precursor. The store of phage precursor in activated cells is destroyed by sonic waves in about 30 minutes. The number of cells (plate count) shows no reduction until after the precursor is entirely inactivated.

4. Attempts to extract phage precursor from activated staphylococci by exposing the cells to sonic vibrations were unsuccessful.
X-RAY AND CRYSTALLOGRAPHIC STUDIES OF PLANT VIRUS PREPARATIONS. III
Authors: Bernal J. D. , Fankuchen I.
Published: May 2004

These papers give an account of an optical and x-ray examination of preparations of plant virus substances isolated by Bawden and Pirie, in particular of those of tobacco mosaic disease. They open with a historical survey of the work, indicating the order in which new phenomena were discovered. The subsequent treatment is divided into three parts:

I. Introduction and preparation of specimens.

II. Modes of aggregation of virus particles.

III. (1) The structure of the particles.

(2) Biological implications.

Part I, after an historical introduction, describes the method of preparation, from solutions of the virus, of optically oriented specimens of different concentrations. For their examination special x-ray apparatus was developed, in particular cameras working with very low angles and capable of indicating spacings up to 1000 Å.

In Part III, Section 1 deals with the x-ray evidence on the internal structure of the particles. Even in solution, they have an inner regularity like that of a crystal. Virus preparations are thus in a sense doubly crystalline. Closer analysis reveals that the x-ray patterns are not directly comparable to those of a crystal as many of the reflections do not obey Bragg's law, but can be understood on the theory of gratings of limited size. The structure seems to consist of sub-units of the dimensions of approximately 11 Å cube, fitted together in a hexagonal or pseudohexagonal lattice of dimensions—a = 87 Å, c = 68 Å. Contrary to what earlier observations seemed to indicate, the particle seems to be virtually unchanged by drying and must therefore contain little water. There are marked resemblances with the structure of both crystalline and fibrous protein, but the virus structure does not belong to any of the classes hitherto studied. There are indications that the inner structure is of a simpler character than that of the molecules of crystalline proteins.

Part III, Section 2 contains a comparative study of the optical and x-ray examinations of three strains of tobacco mosaic virus, two of cucumber disease virus, two of potato virus X, and the virus of bushy stunt disease of tomato. In the last case x-ray measurement confirmed the deduction from its cubic crystal habit that it was composed of spherical rather than long particles, and showed that these had a diameter when dry of 276 Å and were arranged in a body-centred cubic close packing. This single example is sufficient to show that the elongated particle form which gives rise to all the anomalous physical properties of the other viruses studied is of no essential biological importance. The similarity and differences observed between the physical properties of these preparations run closely parallel to their clinical and serological classification. Finally, the biological implications of these results are discussed together with possible applications of the new methods of examination to the study of colloid and biological problems.
DETERMINATION OF CERTAIN AMINO ACIDS IN CHYMOTRYPSINOGEN, AND ITS MOLECULAR WEIGHT
Authors: Brand Erwin , Kassell Beatrice
Published: May 2004

1. A preparation of chymotrypsinogen, obtained from Dr. M. Kunitz, was analyzed for sulfur, the sulfur amino acids, tyrosine, and tryptophane.

2. The protein sulfur of chymotrypsinogen was accounted for as methionine, cysteine, and cystine.

3. A method is presented for calculating the minimum molecular weight of a protein from the distribution of the sulfur amino acids. In the case of chymotrypsinogen, the calculated minimum molecular weight was found to be the actual molecular weight.

4. The molecular weight of chymotrypsinogen is 36,700 by amino acid analysis as compared to 36,000 by osmotic pressure measurements of Kunitz and Northrop. Chymotrypsinogen contains per mol 17 atoms of sulfur, 3 residues of methionine, 4 of cysteine, 10 of half-cystine (i.e. 5 S—S linkages), 6 of tyrosine, and 10 of tryptophane.

5. The tryptophane content of chymotrypsinogen (5.51 per cent) is the highest of any protein so far on record.

6. Chymotrypsinogen contains no reactive SH groups, although it yields cysteine on hydrolysis. This may be due either to preformed but unreactive SH groups or to S—X groups. The term S—X group is used to denote the substitution of the sulfhydryl hydrogen by a constituent X; hydrolysis yields SH groups: S—X + HOH = SH + X—OH.
A SIMPLE TIME WEIGHT RELATION OBSERVED IN WELL NOURISHED RATS
Authors: Zucker Lois , Zucker Theodore F.
Published: May 2004

The equation

See PDF for Equation

fits the growth of well nourished rats from weaning on. The general properties of the equation, and particularly its relation with the law of relative growth, are discussed.
THE PHYSIOLOGICAL EFFECTS OF l-TYROSINE AND l-PHENYL-ALANINE ON THE RATE AND QUALITY OF PULSATION IN THE SEVENTY-TWO HOUR EXTIRPATED EMBRYONIC CHICK HEART
Authors: Miller Bernard J. , Ciacci Vincent W.
Published: May 2004

1. 72 hour isolated chick hearts show an increase in pulsation rate when placed in M/1000, M/10,000, and M/50,000 l-tyrosine solutions. The optimal effect is seen in M/10,000 and M/50,000 l-tyrosine.

2. All hearts show disturbance of rhythm either in the form of irregular rhythm or heart block.

3. 62 hour isolated chick hearts are not susceptible to l-tyrosine while 96 hour hearts are markedly sensitive.

4. 72 hour isolated chick hearts placed in 1 part in 10,000 and 1 part in 50,000 l-epinephrine show approximately the same effects as were seen with l-tyrosine.

5. 72 hour isolated chick hearts placed in M/1000 and M/10,000 l-phenylalanine show an initial depression followed by an l-tyrosine effect.
THE FLOCCULATION MAXIMUM (pH) OF FIBRINOGEN AND SOME OTHER BLOOD-CLOTTING REAGENTS. (RELATIVE TURBIDIMETRY WITH THE EVELYN PHOTOELECTRIC COLORIMETER)
Authors: Ferguson John H.
Published: May 2004

By means of a novel adaptation of the Evelyn photoelectric colorimeter to the measurement of relative turbidities, the question of the flocculation maximum (F.M.) in acetate buffer solutions of varying pH and salt content has been studied on (a) an exceptionally stable prothrombin-free fibrinogen and its solutions after incipient thermal denaturation and incomplete tryptic proteolysis, (b) plasma, similarly treated, (c) prothrombin, thrombin, and (brain) thromboplastin solutions.

All the fibrinogens show a remarkable uniformity of the precipitation pattern, viz. F.M. =4.7 (±0.2) pH in salt-containing buffer solutions and pH = 5.3 (±0.2) in salt-poor buffer (N/100 acetate). The latter approximates the isoelectric point (5.4) obtained by cataphoresis (14). There is no evidence that denaturation or digestion can produce any "second maximum." The data support the view that fibrin formation (under the specific influence of thrombin) is intrinsically unrelated to denaturation and digestion phenomena, although all three can proceed simultaneously in crude materials. A criticism is offered, therefore, of Wöhlisch's blood clotting theory.

Further applications of the photoelectric colorimeter to coagulation problems are suggested, including kinetic study of fibrin formation and the assay of fibrinogen, with a possible sensitivity of 7.5 mg. protein in 100 cc. solution.
THE PREPARATION AND USE OF TOBACCO MOSAIC VIRUS CONTAINING RADIOACTIVE PHOSPHORUS
Authors: Stanley W. M.
Published: May 2004

Normal and tobacco mosaic-diseased Turkish tobacco plants were grown in sand for a period of several weeks, during which they were fed daily a complete nutrient solution to which had been added disodium phosphate containing radioactive phosphorus. Determinations were made of the distribution of radioactive phosphorus in different fractions such as the wash from the sand and roots, the press cake obtained on pressing the juice from the plants, the protein and protein-free portions of the supernatant liquids obtained on ultracentrifugation of the juices, and the purified tobacco mosaic virus isolated from the diseased plants. Chemical analyses as well as radiographs of the normal and diseased leaves indicated that they contained the same amount of phosphorus. Approximately 30 per cent of the radioactive phosphorus absorbed by the diseased plants was found to be combined with the purified tobacco mosaic virus that was isolated from these plants. Following the inoculation of purified tobacco mosaic virus possessing high radioactivity to normal Turkish tobacco plants, most of the radioactivity was found to be associated with non-virus components of which about 40 per cent was in the inoculated and 60 per cent in the uninoculated portions of the plants. Although a small amount of radioactive virus was isolated from the uninoculated portions of the plants, it was impossible, because of a number of complicating factors which have been discussed, to draw from the results any reliable conclusions regarding the mode of reproduction of tobacco mosaic virus.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Sollner Karl , Carr Charles W.
Published: May 2004

1. Experiments were carried out to decide whether a homogeneous phase (solubility) theory or a micellar-structural theory more adequately describes the behavior of dried collodion membranes with solutions of strong electrolytes.

2. A number of dried collodion membranes were prepared from an electrochemically inactive collodion preparation (state I); the characteristic concentration potentials across them were low, about 30 mv. The membranes were activated by oxidation (state II) to give maximum or nearly maximum concentration potentials (about 50 mv.). The oxidized membranes are dried, dissolved in alcohol-ether, and a new set of dry collodion membranes prepared from this solution (state III). The concentration potentials across these membranes are low.

3. Since the properties of a homogeneous phase should not be influenced by a rearrangement of its constituent particles, the experimental results do not support a homogeneous phase (solubility) theory, but they agree with the predictions of the micellar-structural theory. The characteristic behavior of dried collodion membranes in solutions of strong inorganic electrolytes is therefore due to the micellar character of its interstices.
THE ANTIPROTEOLYTIC ACTIVITY OF SERUM
Authors: Grob David
Published: May 2004

1. Serum antitrypsin and pancreatic trypsin inhibitor inhibited the coagulation of plasma in vitro.

2. This could be largely prevented by trypsin.

3. The anticoagulant action of the trypsin inhibitor was apparently due to its antiprothrombic action. It had no appreciable antithrombic action.

4. Examination of the blood of two hemophiliacs indicated that the prolonged coagulation time of their blood is not due to an excess of trypsin inhibitor.

5. Examination of the blood of heparinized dogs indicated that heparin does not appreciably contribute to the antiproteolytic activity of the serum.
THE MECHANISM OF THE INHIBITION OF HEMOLYSIS
Authors: Ponder Eric
Published: May 2004

The principal conclusion of this investigation is that the inhibitory effect of plasma or serum on hemolysis by saponin and lysins of the same type is similar in nature to the inhibitory effects of certain sugars and electrolytes, which again are similar to the acceleratory effects produced by indol, benzene, and other substances already studied. All these effects, both inhibitory and acceleratory, are the result of reactions between the inhibitors or accelerators and those components of the red cell membrane which are broken down by lysins.

The inhibitory effect of plasma on saponin hemolysis has a number of properties in common with the inhibition produced by sugars and electrolytes and with accelerations in general. (a) The temperature coefficient is small and negative. (b) The extent of the inhibition depends on the type of red cell used in the hemolytic system. (c) The most satisfactory measure of the extent of the inhibition, the constant R, is a function of the concentration of lysin in the system, and (d) R is a linear function of the quantity of inhibitor present.

It is also shown that the inhibitory effect of plasma, and serum is not entirely dependent on its protein content.

The process underlying the phenomenon of lysis and its acceleration or inhibition seems to be one in which the lysin reacts with a component or components of the cell membrane in such a way as to break down its semipermeability to hemoglobin, and in which the accelerator or inhibitor also reacts with the same component in such a way as to increase or decrease the effectiveness of the lysin in producing breakdown. The membrane is considered as being an ultrastructure made up of small areas or spots of varying degrees of resistance to breakdown, the resistances being distributed according to a negatively skew type of frequency curve, and the process of lysis seems to begin with the least resistant spots breaking down first. These spots may be arranged in some regular spatial pattern, and the membrane has also to be regarded as possessing spots of varying rigidity of form. The accelerator or inhibitor changes the resistance of every reactive spot in the ultrastructure by a factor R, which suggests that acceleration and inhibition are results of some over-all effect, such as that of changing the extent to which lysin is concentrated at the surface or partitioned between the material of the membrane and the surrounding fluid. Some kind of combination between the accelerator or inhibitor and the material of the ultrastructure is presumably involved; at first the combination seems to be a loose one and partly reversible, but later some of the loose links are replaced by more permanent combinations involving the same types of bond as are broken down by the lysins themselves.
NATURE OF THE ACTION CURRENT IN NITELLA
Authors: Osterhout W. J. V.
Published: May 2004

When a stimulus arrives before recovery is complete there may be no response or only a partial response. A typical response appears to involve an immediate loss of potential at the inner protoplasmic surface but not at the outer surface. As long as recovery is incomplete only a part of the total potential is located at the inner protoplasmic surface and the loss of this part of the total potential can cause only a partial response; i.e., one of smaller magnitude than the normal.

Even after the action curve has returned to the base line recovery may be incomplete and the response only a partial one. The return of the action curve to the base line means a recovery of total potential but if part of this is located at the outer protoplasmic surface and if this part is not lost when stimulation occurs the response can be only a partial one. During recovery there is a shift of potential from the outer to the inner protoplasmic surface. Not until this shift is completed can recovery be called complete. The response to stimulation then becomes normal because the loss of potential reaches the normal amount.

In many cases the partial responses appear to conform to the all-or-none law. In other cases this is doubtful.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Carr Charles W. , Sollner Karl
Published: May 2004

1. The assumption, has generally been made that collodion membranes are rigid and non-swelling in water and aqueous solutions of strong electrolytes, and considerable uncertainty exists as to the manner in which water is taken up by "dried" collodion membranes. In approaching these problems experimentally, the weight and volume changes of collodion membranes when placed in water and when transferred from water to solutions of strong electrolytes were determined.

2. Dried collodion membranes swell reversibly to an appreciable extent when placed in water, the swelling varying from 5 to 11 per cent depending on the brand of collodion. The water uptake and swelling of oxidized collodion is the same as the original unoxidized preparation.

3. The water uptake as determined by the weight increase is larger than could be accounted for by the volume increase, swelling accounting for only 60 to 70 per cent of the water taken up by the membranes.

4. When the "water-wetted dried" collodion membranes were transferred from water to solutions of various strong electrolytes, there was no detectable change in volume. Similarly, when the "porous" membranes were transferred from water to solutions of strong electrolytes, there was no significant volume change.

5. When dried collodion membranes swell in water, some of the water becomes "bound" water, and both intramicellar and intermicellar swelling seem to occur. Therefore, neither the weight increase nor the volume increase nor their difference can be taken as a measure of the true pore space of the membrane. It is concluded that the important problem is not the absolute water content, but how much water in the water-wet membranes is available in useful pathways for the different solutes.
FLICKER RESPONSE CONTOURS FOR THE SPARROW, AND THE THEORY OF THE AVIAN PECTEN
Authors: Crozier W. J. , Wolf Ernst
Published: May 2004

The flicker contour for the house sparrow Passer domesticus is duplex, corresponding to the presence of both rods and cones in the retina. The presence of the pecten brings about changes in the "cone" part of the contour when the light-time in the flash cycle is varied. These changes are of the same sort as those we have already described for the visually simplex zebra finch, and for man provided with an artificial "pecten shadow." The changes are such as to greatly enhance flicker acuity for small dark-times (moving stripe technique). The form of the scotopic part of the duplex contour (also as in the case with man) gives no evidence that rod excitation is specifically influenced by the presence of the pecten. The changing integration of "rod" and "cone" effects as the light-time fraction is altered provides another means of testing the theory used for the analytical separation of the two components of the duplex flicker contour.
I. THE RELATION BETWEEN ATTACHMENT TO THE SUBSTRATUM AND INGESTION BY AMEBA IN STRYCHNINE SULFATE SOLUTION AND CONDITIONED MEDIA
Authors: Fennell Richard A.
Published: May 2004

1. Strychnine sulfate 0.000069 M decreased percentage attachment to the substratum by Amoeba proteus in 0.0029 M NaCl from 77.3 to 1.3, in 0.0029 M KCl from 40.8 to 2.5, in 0.002 M CaCl2 from 73.3 to 68.0, in 0.002 M MgCl2 from 85.5 to 83.3.

2. Frequency of ingestion of chilomonads by Amoeba proteus is increased by adding strychnine sulfate to solutions of NaCl, KCl, or CaCl2. Frequency of ingestion is increased in NaCl solution from 1.3 to 2.3, in KCl from 0.75 to 2.25, and in CaCl2 from 1.1 to 1.9 chilomonads per minute. Ingestion is not significantly increased by the addition of strychnine to MgCl2 solution.

3. Frequency of ingestion of food by Amoeba proteus is not closely correlated with attachment to the substratum in NaCl and KCl solutions to which strychnine sulfate is added.

4. Chilomonads adhere to the plasmalemma of Amoeba proteus in solutions of NaCl, KCl, or CaCl2 containing strychnine, but in MgCl2 plus strychnine only a few adhere to it. Strychnine appears to make the surface of the amebae and chilomonads sticky in the former but not in the latter. Frequency of ingestion is apparently correlated with adherence of chilomonads to the plasmalemma.

5. Attachment to the substratum and ingestion by Pelomyxa carolinensis is increased by dead Chilomonas, Colpidium, and Paramecium in aqueous solutions, by materials obtained from paramecia by alcoholic-ether extraction, and by solutions in which these organisms have lived.

6. Attachment to the substratum by Pelomyxa carolinensis is not closely correlated with kind or concentration of inorganic salts used in this study.

7. Materials were found in extracts of paramecia which had certain characteristics in common with choline esters. There is no reason to doubt that under certain conditions materials are present in aqueous and alcoholic extracts which are pharmacologically similar to choline and acetylcholine.

8. Aqueous suspensions of paramecia when subcutaneously injected into young mice for 21 days inhibit the gonadotropic luteinizing hormone of the pituitary. Ovaries from injected mice showed no corpora lutea, and the seminal vesicles from injected males were smaller and contained less fluid than those of the controls.
THE STRUCTURE OF THE COLLODION MEMBRANE AND ITS ELECTRICAL BEHAVIOR
Authors: Sollner Karl , Carr Charles W.
Published: May 2004

1. The Teorell, Meyer-Sievers theory characterizes the electrochemical behavior of membranes by their selectivity constant "Ap" which is derived conventionally from concentration potential measurements at various concentration levels. The selectivity constant may, however, be derived also from entirely independent, different experimental data, namely base exchange studies. The constants arrived at in this second way are designated as "Ab." The selectivity constants derived by these two methods must be in reasonable, at least semiquantitative agreement if the basic assumptions of the theory are correct.

2. The selectivity constants Ap and Ab were determined for eleven different sets of membranes of different electrochemical activity and of different (8.2 to 80 volume per cent) water content.

3. The potentiometric selectivity constants Ap are in most cases several orders of magnitude greater than the corresponding Ab values. With membranes of great porosity and high electrochemical activity the Ab values approach at least in order of magnitude the Ap values.

4. It is concluded that the unexpectedly large discrepancy between the Ap and Ab values is due to some inherent weakness of the Teorell, Meyer-Sievers theory, most likely to its neglect of any structural factors.
STUDIES OF THE INNER AND OUTER PROTOPLASMIC SURFACES OF LARGE PLANT CELLS
Authors: Osterhout W. J. V.
Published: May 2004

The vacuolar surface of Nitella is covered with a non-aqueous film too thin to be visible as a separate membrane. The motion of the protoplasm may subject this film to a good deal of mechanical disturbance.

Apparently this does not rupture the film for no dye escapes into the protoplasm as the result of such disturbance when the vacuolar sap is deeply stained with neutral red or brilliant cresyl blue.

When the deeply stained central vacuole breaks up into several smaller vacuoles, leaving the outer protoplasmic surface in its normal position, there is no evidence of the escape of dye into the protoplasm through the film surrounding the vacuole.
THE MECHANISM OF THE INHIBITION OF HEMOLYSIS
Authors: Ponder Eric
Published: May 2004

The effects of variations of pH, from 5.6 to 8.6, on the lytic activity of saponin, digitonin, and sodium taurocholate, and the effects on the inhibition produced by plasma and by cholesterol sols, are described. The results, so far as they can be analyzed, show that the pH dependence of the inhibition produced by plasma is different from that of the inhibition produced by cholesterol sols, and this leads to the conclusion that a considerable part of the inhibition produced by plasma is due to inhibitory substances other than cholesterol. The results also provide a certain amount of indirect evidence that hemolysis is not due primarily to a reaction of the lysins with the cholesterol of the red cell membrane.
THE PARACRYSTALLINE STATE OF THE RAT RED CELL
Authors: Ponder Eric
Published: May 2004

When washed rat red cells are kept in 3 per cent sodium citrate at low temperatures (4–9°C.), their resistance to osmotic hemolysis increases so that after several days they swell very little in hypotonic solutions (R = 0.15 to zero) and do not hemolyze even in distilled water. In this and in other respects they behave as if they were gelated or paracrystalline. The paracrystalline state is reversible, disappearing when the cells are warmed and rapidly reappearing when they are cooled, and the resistance to hypotonic hemolysis is not due to the cells reaching equilibrium with their environment by losing so much K that the concentrations become equal inside and out. The concentration of K remains about 25 times as great inside the cell as outside it in a hypotonic medium of T = 0.1, and the failure to swell and to hemolyze seems to be due to the activity of K in the interior of the paracrystalline cell approaching zero. The paracrystalline red cells are more resistant to saponin and digitonin hemolysis, and do not undergo the usual shape transformations, probably because they are too rigid. Hemolysis by saponin and similar lysins occurs without sphere formation, and after lysis is complete a granular debris is left behind. The paracrystalline cells show a diffuse birefringence with polarized light; on their being warmed, the birefringence disappears except at foci which are usually situated along the rim of the cell.

The occurrence of the paracrystalline state accounts for the different amounts of swelling of red cells which have been observed in systems of the same degree of hypotonicity, and its relation to other metastable states of the red cell is discussed in connection with a tabulation of the metastable states of the mammalian red cell and their relation to one another. Changes in a membrane alone seem inadequate to account for the varied phenomena observed in connection with red cell behavior, the explanation of which appears to require a more detailed knowledge of the molecular architecture of the cell interior.
SOME PROPERTIES OF THE YEAST YELLOW PROTEIN
Authors: Ball Eric G.
Published: May 2004

The yeast yellow protein contains two prosthetic groups, one of which is undoubtedly a flavin. The nature of the other is unknown, though some of its properties are described.

No catalytic function for this protein has as yet been found.
OBSERVATIONS ON THE RESPIRATION OF TRYPANOSOMA CRUZI IN CULTURE
Authors: von Brand Theodor , Johnson Eleanor M. , Rees Charles W.
Published: May 2004

1. The oxygen consumption of cultural forms of Trypanosoma cruzi decreases in intensity with increasing age of the cultures; no correlation with any other factor studied could be established.

2. The respiratory quotient was high for the first 10 days, i.e. as long as the population increased; with the onset of a decline in numbers, the R.Q. began to drop. It is believed that the flagellates consume in the beginning predominantly sugar and later predominantly protein. Observations on the pH of the cultures bear out this view.

3. The oxygen consumption was independent of the oxygen tension over a wide range of tensions.

4. The oxygen consumption increased in the temperature range 13° to 40°C., while a temperature of 44°C. proved to be lethal. Upon application of Arrhenius' equation, two straight lines, intersecting at about 28°C., resulted. The µ values were 23,980 and 5275 for the lower and higher temperature range respectively.

5. Of the oxidase inhibitors tested, strong inhibition of the oxygen consumption was achieved with azide, cyanide, and hydrogen sulfide. Pyrophosphate had no influence at all. There is some probability that cytochrome oxidase is the chief oxidase present.

6. The strongest inhibitory influence due to dehydrogenase inhibitors was observed with propyl carbamate and high concentrations of ethyl carbamate.

7. A small fraction of the oxygen consumption, about 10 per cent, may be due to substances with sulfhydryl groups, as indicated by a slight but distinct inhibition due to dilute iodoacetate and to arsenite.
SOME PROPERTIES OF PROTOPLASMIC GELS
Authors: Osterhout W. J. V.
Published: May 2004

The chloroplasts of Nitella may contract under natural conditions as well as under the influence of certain reagents. When a sufficient amount of water enters any part of the cell they contract in that region and they expand when the direction of the current is reversed. The current may be produced by placing water at one end of the cell and applying at the other end a solution which withdraws water from the cell.

The contraction may be due to the washing out of substances from the chloroplast by the ingoing current. The outgoing current bearing dissolved materials from the sap may restore these substances and cause the chloroplasts to resume their normal shape. When blood or sodium dodecylsulfate is present in the ingoing current the contraction of the chloroplast usually fails to occur.
THE SULFONIUM SALT OF MUSTARD GAS: BIS-ß-[BIS(ß-HYDROXYETHYL) SULFONIUM] ETHYLSULFIDE DICHLORIDE (H·2TDG)
Authors: Herriott Roger M.
Published: May 2004

1. The sulfonium salt H·2TDG is formed when H is mixed with even dilute solutions of TDG. Crystalline H·2TDG was isolated from such a reaction mixture. A simple method of preparation of this salt is outlined.

2. A material which differs from H·2TDG in that it hydrolyzes faster, is formed when H hydrolyzes in water. This material is probably H·1TDG but it was not isolated. Approximately 5 to 8 per cent of the original H is converted to this sulfonium salt.

3. The hydrolysis constant of M/100 H·2TDG has been determined at 20°, 25.5°, 37°, 75°, and 100°C., a temperature coefficient, Q10, of 3–4 was obtained. The effect of temperature is in agreement with that predicted by the Arrhenius equation. An activation energy of 26,000 calories was calculated.
THE BEHAVIOR OF THE NUCLEIC ACIDS DURING THE EARLY DEVELOPMENT OF THE SEA URCHIN EGG (ARBACIA)
Authors: Schmidt Gerhard , Hecht Liselotte , Thannhauser S. J.
Published: May 2004

1. The unfertilized Arbacia egg contains an average of 20γ x 10–3 ribonucleic acid and 0.7 to 1γ x 10–3 desoxyribonucleic acid.

2. During the first 24 hours of development, the amount of ribonucleic acid per embryo remains practically unchanged whereas that of desoxyribonucleic acid steadily increases. At the end of this period, the amount of desoxyribonucleic acid per embryo is 10 to 15 times larger than that of the unfertilized egg.
THE EFFECTS OF LOW TEMPERATURE ON FERTILIZED RABBIT OVA IN VITRO, AND THE NORMAL DEVELOPMENT OF OVA KEPT AT LOW TEMPERATURE FOR SEVERAL DAYS
Authors: Chang M. C.
Published: May 2004

Fertilized rabbit ova at the 2-blastomere stage kept in rabbit serum were stored at low temperatures for various lengths of time. They were then cultured at 38°C. for about 24 hours to determine their viability. A number of the viable ova were finally transplanted into recipient does.

It was found that rapid cooling of ova to 5° or to 0°C. was more harmful to the subsequent viability of ova than slow cooling. Rapid cooling was not more lethal to the ova than slow cooling, but did prevent their future normal cleavage. There was no difference between those ova cooled rapidly or slowly to 10°C. It was concluded that temperature shock has an adverse effect on ova, especially at the lower temperatures, though temperature shock can be remedied by acclimatization (slow cooling). Thus, the physiological significance of temperature shock would seem to be broadened.

The optimal temperature for the storage of ova was investigated. It was found that 10°C. was the best temperature; at this temperature viable ova were obtained after storage for 144 to 168 hours. At 0°, 5°, or 15°C. the ova were viable for 96 to 120 hours, while at 22–24°C., only for 24 to 48 hours.

The percentage of dead ova was low at a favorable temperature, increasing only at the end of the storage period. At an unfavorable temperature, however, the rate of death increased steadily from beginning to end of storage.

The percentage of abnormally cleaved ova (arrested cleavage and fragmentation) remained at a low level at first at a favorable temperature, but then increased just before or during death of the ova.

A critical time for the viability, the abnormal cleavage, and the death of ova was characteristic of each temperature.

About 24 to 28 per cent of the viable ova remaining after being stored at 0–15°C. for 2 to 4 days and cultured at 38°C. for 24 hours were capable of development into normal young.

The compatibility of serum and ova, the absence of a correlation between the viability of the ova and the source of the fertilizing spermatozoa, and the fertilization of superovulated ova (i.e., the percentage of fertile does in follicular phase and in luteal phase, the percentage of unfertilized ova and of fertilized ova at different stages, the percentage of does that had produced a normal number of ova or had produced a large number of ova, etc.), are reported.

The possibility of a more efficient utilization of the germ cells of valuable animals by means of the present techniques, and the possibility of a new approach to the experimental investigation of mammalian genetics and development, have been mentioned.
THE RELATION BETWEEN VISUAL ACUITY AND BRIGHTNESS DISCRIMINATION
Authors: Hendley Charles D.
Published: May 2004

1. Visual acuity depends on the brightness contrast between test object and background; and conversely, brightness discrimination depends on the target size. Both functions vary with the brightness of the background. Measurements with rectangular targets of length-width ratio 2 were made over a range of sizes, contrasts, and brightnesses sufficient to determine the relations among these three variables. The rectangles were from 2' to 50' wide; the contrast fraction, ΔI/I, ranged from 0.01 to 40; the background brightness varied from 0.0001 to 2500 millilamberts.

2. When ΔI/I or visual acuity is plotted as a function of brightness the data do, in general, follow Hecht's equation. The departure from a simple photochemical theory which the larger targets show is probably due to changes in the functional retinal mosaic with changing brightness.

3. In general also, the relation between visual acuity and brightness, at selected contrasts, fits Hecht's derivation. At low contrasts, as the brightness is reduced a point is reached at which the test object becomes invisible at any size.

4. No simple relation emerges from the data relating visual acuity to contrast, at set levels of illumination. Over only a very short range are visual acuity and contrast directly related. At high contrasts, visual acuity reaches a maximum, whereas at low visual acuity, ΔI/I reaches a minimum which cannot be passed regardless of size.

5. The shape of the curves relating ΔI/I to brightness is not significantly altered by changing the exposure time. There is some evidence to show that a 3 second exposure of the target is equivalent to two looks of 0.2 second each.

6. In all these studies the thresholds were determined by a frequency of seeing method, and the data have been considered in terms of a quantum theory of threshold seeing. It was found that a threshold response involves between four and eight independent critical events, which are largely independent of size, brightness, and criterion of seeing.
THE VISUAL FUNCTIONS OF THE COMPLETE COLORBLIND
Authors: Hecht Selig , Shlaer Simon , Smith Emil L. , Haig Charles , Peskin James C.
Published: May 2004

1. The visual functions of a completely colorblind individual are compared with those of the normal. The sensibility distribution in the spectrum has a maximum at 520 mµ at all brightnesses and thus corresponds to rod vision alone. This is confirmed by studies of dark adaptation which show final thresholds like those usually found for rod vision. Dark adaptation, measured both centrally and peripherally in the retina, is a single continuous function, and regardless of the brightness of the preceding light adaptation, is of the rapid type only, such as that found for the normal following low light adaptation. Visual acuity also shows a single continuous function like that for rod vision.

2. Both critical fusion frequency and intensity discrimination show two sections, one at low and the other at high intensities with a sharp transition from one to the other. Intensity discrimination is as good as for the normal eye, and covers much the same range. The maximal critical fusion frequency is only about 20 cycles per second as compared to 55 cycles for the normal.

3. The two sections shown by the colorblind eye for intensity discrimination and fusion frequency possess the spectral sensitivity of rod vision since the relative positions on the intensity scale are not influenced by using different parts of the spectrum.
THE PROTECTIVE EFFECT OF SODIUM CHLORIDE AGAINST THERMAL DESTRUCTION OF THE PHAGE-FORMING MECHANISM IN STAPHYLOCOCCI
Authors: Fong Jacob
Published: May 2004

Staphylococci which have been allowed to grow rapidly in a favorable environment and subsequently have been maintained in a resting state characteristically produce a sharp rise in [phage] activity titre when added to phage. This capacity is quickly lost when the cells are suspended in distilled water and are exposed to 44° C. for a period of 15 minutes; at the same time the viable count drops to approximately 1 to 3.5 per cent of the initial value. 1 M NaCl protects "activated" cells against thermal destruction and preserves the phage-augmenting property. "Non-activated" staphylococci in distilled water suspension do not show this thermolability.
THE FORMATION OF BACTERIAL VIRUSES IN BACTERIA RENDERED NON-VIABLE BY MUSTARD GAS
Authors: Herriott Roger M. , Price Winston H.
Published: May 2004

E. coli B and Staphylococcus muscae rendered non-viable by aqueous solutions of mustard gas at pH 7.5 to 8 can still produce phage.
THE KINETICS AND THERMODYNAMICS OF REVERSIBLE DENATURATION OF CRYSTALLINE SOYBEAN TRYPSIN INHIBITOR
Authors: Kunitz M.
Published: May 2004

Crystalline soybean trypsin inhibitor protein undergoes denaturation on heating which is reversed on cooling. In the range of temperature of 35 to 50°C. a solution of the protein consists of a mixture of native and denatured forms in equilibrium with each other. The equilibrium is only slowly established and its final value at any temperature is the same whether a heated, denatured solution of the protein is cooled to the given temperature or whether a fresh solution is raised to that temperature. The kinetics of reversible denaturation of the soybean protein as well as the reversal of denaturation is that of a reversible unimolecular reaction, each process consisting at a given temperature of the same two simultaneous reactions acting in opposite directions.

The experimental data on the effect of temperature on the velocity and the equilibrium constants of the opposing reaction were utilized in evaluating the reaction energies and activation energies.

The reaction energies for denaturation were found to be as follows:—

Change in total heat of reaction ΔH = 57,000 calories per mole

Change in entropy of reaction ΔS = 180 calories per degree per mole

The heat of activation ΔH1‡ for denaturation = 55,000

The heat of activation ΔH2‡ for the reversal of denaturation = –1900

The entropy ΔS1‡ for denaturation = 95

The entropy ΔS2‡ for reversal of denaturation = –84
DINITROCRESOL AND PHOSPHATE STIMULATION OF THE OXYGEN CONSUMPTION OF A CELL-FREE OXIDATIVE SYSTEM OBTAINED FROM SEA URCHIN EGGS
Authors: Crane Robert K. , Keltch Anna K.
Published: May 2004

1. A cell-free system capable of using oxygen with oxalacetate as substrate has been prepared from both unfertilized and fertilized sea urchin eggs. The oxygen uptake by this system is about twice that of an equivalent quantity of intact unfertilized eggs and half that of an equivalent quantity of intact fertilized eggs.

2. The oxygen consumption of this cell-free oxidative system can be stimulated by addition of suitable concentrations of 4,6-dinitro-o-cresol or by inorganic phosphate. This confirms, with a cell-free system obtained from sea urchin eggs, the observations of Loomis and Lipmann regarding stimulation of oxygen consumption by a system obtained from rabbit kidney.

3. A preliminary but unsuccessful attempt has been made to determine the conditions under which cell-free, aerobic, phosphorylating systems may be obtained from either unfertilized or fertilized sea urchin eggs.
THE LOCI OF ACTION OF ULTRAVIOLET AND X-RADIATION AND OF PHOTORECOVERY IN THE EGG AND SPERM OF THE SEA URCHIN ARBACIA PUNCTULATA
Authors: Blum Harold F. , Robinson J. Courtland , Loos Gordon M.
Published: May 2004

Various experiments are described which show the locus of action of ultraviolet radiation and of x-ray in delaying cell division of the fertilized egg of Arbacia punctulata to be in the nucleus.

Photorecovery following ultraviolet radiation has its locus in the egg cytoplasm.

Analogy is drawn with the action of ultraviolet radiation and photorecovery on the E. coli-bacteriophage system, and certain suggestions are made regarding a common mechanism.

Photorecovery after x-ray exposure could not be demonstrated.
ADRENALIN AND HYDROXYTYRAMINE IN THE PAROTID GLAND VENOM OF THE TOAD, BUFO MARINUS
Authors: Gregerman Robert I.
Published: May 2004

Preparations from the parotid gland venom of the toad Bufo marinus have been analyzed by paper chromatography for the presence of adrenalin precursors. In addition to adrenalin itself, hydroxytyramine was identified and a second compound which appeared to be an adrenalin ester—perhaps lactyl-adrenalin. Two other compounds which appeared on the chromatogram could not be identified. Neither noradrenalin nor another possible precursor, epinine, appeared to be present.
DELAYED HEMOLYSIS OF HUMAN ERYTHROCYTES IN SOLUTIONS OF GLUCOSE
Authors: Hendry Edward B.
Published: May 2004

There has been described a type of hemolysis which occurs under certain defined conditions when erythrocytes are suspended in glucose solution. It consists of a prolytic phase lasting about an hour, followed by a hemolytic phase lasting about 2 hours. The physical factors controlling this delayed hemolysis have been investigated. The system is especially sensitive to changes of pH and of temperature.

This type of hemolysis is inhibited by increased osmotic pressure and by phlorhizin, but not, as far as can be ascertained, by fluoride or iodoacetate.

It is possible, but not yet proved, that delayed hemolysis in glucose solution is dependent on enzymic activity. Phosphorylation may be the limiting factor.

During the prolytic phase the cells are easily permeable to potassium. It is concluded that the development of cation permeability is not a direct cause of hemolysis.