Greater Acid Research Articles

Points from Foregoing Letters

THE addition of echo sounding gear to the Johan Hjort enabled that vessel to reveal unsuspected features of the flooring of deep fjords, and to locate swarms of spawning cod in the neighbourhood of Lofoten. These, writes Oscar Sund, were mainly in a layer of 10–12 metres thick at a constant depth where a somewhat lower oxygen concentration and greater acidity could also be detected.

Rate of Growth and Acid Production of Streptococcus lactis

Summary By segregating the fast growing strains from those which grow more slowly in stock cultures of Streptococcus lactis , it has been shown that slow growth is associated with greater acid tolerance. The conclusion is drawn that such a relationship exists among strains of the same genetic constitution.

Micro acidimetry of nitrophenols with the glass electrode

A comparatively rapid and precise potentiometric method for the micro determination of the nitro phenols with greater acid ionization constants than 10−8 has been given. The method employs the glass electrode as the indicator of hydrogen ion activity and a vacuum tube galvanometer for the null instrument.

The Work of the Kidney in the Production of Urine

The work performed by the kidney in the production of urine appears to be more readily susceptible of analysis by means of the laws of thermodynamics than any other complete function of the animal body. The recognition of this possibility, of course, is not new. It has attracted a number of investigators whose essays have been collected and reviewed by Cushny [1]. The purpose and method were essentially the same in all of these studies: the computation of the theoretical minimum amount of work necessary to elaborate a solution such as urine from another such as blood. None of these computations was complete; and even in the last, made in 1914 [2], a number of processes were not taken into account, viz.: the suppression of ionization of the phosphates, and other weak acids by the greater acidity of the urine, and the production of ammonia from urea by the kidney. In the account presented below of the minimum work necessary for the production of the urine, an attempt has been made to appraise the factors omitted in previous studies; and an alternative method has been employed in the analysis of the work involved in the transport of water. It is felt that a clearer understanding of the energetics of water transport in the body in general is obtained from the alternative treatment. The minimum work has been considered as a quantity equal to the sum of the free energy changes for the transport of each constituent, including water, from blood to urine. It has been assumed, an assumption justifiable on practical grounds, that the substances concerned may be considered as perfect solutes.

NITROGEN METABOLISM OF NORMAL AND SARCOMATOUS FIBROBLASTS IN PURE CULTURES

1. Both normal and sarcomatous fibroblasts of the rat utilize many different fragments of the protein molecule for their growth in vitro. Alpha and beta proteoses have approximately equal growth-promoting power. 2. A mixture of peptones, peptides, and amino acids, containing a negligible quantity of proteose, produces a temporary proliferation of normal fibroblasts, and an unlimited multiplication of sarcomatous fibroblasts, provided these substances are derived from liver which contains products of unknown nature that complete the nutritive effect of the protein degradation products. 3. Amino acids contribute to the nutrition of the cells, but are unable without the addition of peptides or polypeptides to support their life. 4. The proteolytic products are more toxic to normal than to sarcomatous fibroblasts. The hypothesis is suggested that the greater acidity produced by the large glycolysis of the sarcomatous cells may account for this difference through altering the speed of action of protein synthetizing enzymes.

THE BEHAVIOR OF FELDSPAR AND FLINT WITH ACIDS AND BASES1

On addition of acids and bases to fine-ground feldspar or flint, the same phenomena are observed as with clays, Le., flocculation, deflocculation, and absorption. The effects are less sharp than with clays, the zone of deflocculation covering a wider range of PH and flocculation occurring at lower pH (greater acidity). The sensitiveness of flint and feldspar to reagents increases with fineness of grinding.

SOME PHYSICOCHEMICAL PROPERTIES OF DISSOCIATED SPONGE CELLS

1. The activity of the hydrogen ion, in a system containing 0.00280 mols of NaAc, 0.520 mols of NaCl per liter, and varied amounts of HCl or NaOH has been investigated. The average value of pK' for acetic add in this system is about 4.37. 2. The effect of the addition of various amounts of HCl and NaOH to a system containing 0.00280 mols of NaAc, 0.520 mols of NaCl, and a known number of cells of either Microciona prolifera or Cliona celata was then studied. It was found that in weak acid solutions Microciona behaves as a stronger base than Cliona, the former being practically saturated with base at a pH of 7.5. Similar behavior is shown by suspensions of cells to which no acid or base was added: the cells of Cliona are more acidic than the cells of Microciona. 3. The microscopic examinations of the cells subjected to the treatment with acid or base indicate that the cells of Microciona remain alive down to pH 4.50; the cells of Cliona sustain greater acidity,- a,t pH 3.7 they exhibit no signs of cytolysis. Tests for aggregation of these cells showed that this phenomenon is greatly inhibited even by slightly acid solutions. 4. The conclusion is drawn that the concentration of cells being equal, the suspensions of cells of Microciona and Cliona differ from each other in their physicochemical properties, the comparison being made on suspensions of specified composition.

ELECTROPHORESIS OF BACTERIA AS INFLUENCED BY HYDROGEN ION CONCENTRATION AND THE PRESENCE OF SODIUM AND CALCIUM SALTS

1. We have confirmed the results of earlier workers particularly of Northrop and De Kruif in regard to the following points: (a) the general tendency of the bacterial cell when suspended in distilled water near the zone of neutrality to move toward the anode of an electrical field; (b) the fact that the migration of bacterial cells in the electrical field is a function of the reaction of the menstruum. The curve obtained by plotting velocity of migration against pH passes through an isoelectric point at about pH 3.0, at greater acidity the direction of migration becomes reversed (toward the cathode) and in still more acid solution (pH = 1.0) again disappears; while at reactions less acid than pH 3.0 the velocity is toward the anode and increases with increasing alkalinity; (c) the fact that neutral salts depress the velocity of migration, calcium salts being much more effective than sodium salts of the same concentration. 2. We further find: (a) that on the extreme alkaline side of the curve of velocity of migration plotted against pH a maximum value is reached at about pH 10 with a fall at about pH 12.0 which in many experiments reaches an isopotential point; (b) that the depressing effect of salts is accompanied by a general shifting of the curve of migration velocity so that a maximum velocity (of course absolutely less than that manifest in the absence of salts) appears at about pH 7.0 and an abolition of velocity at pH 9.0 to 10.0; (c) that an apparent "antagonistic" effect is indicated between CaCl(2) and NaCl, the presence of a certain concentration of the latter salt diminishing to a slight but definite degree the depressing effect produced by the former; (d) that heat-killed bacterial cells exhibit essentially the same curve of migration velocity as that of the living cells; (e) that bacterial spores exhibit the same general curve of migration velocity as vegetative cells, although the actual velocity is apparently slightly less. 3. All of the observed phenomena appear to be in accord with the assumption that marked differences in dielectric constants did not appear under the conditions studied and if this assumption be granted the results are in accord with the fundamental postulates of the Donnan equilibrium as applied to the explanation of the origin of potential difference between a bacterial cell and its enveloping menstruum. It is possible but not at all certain that the phenomenon of antagonism may require the introduction of additional assumptions for its explanation. Professor Donnan and other investigators have clearly understood the importance of applying the concept of membrane equilibria in the elucidation of physiological phenomena. Our findings add to the numerous vindications favoring this view and emphasize the importance of further study of membrane equilibria in bacterial suspensions. We have pointed out that certain potential differences between bacteria and their menstrua are apparently associated with some of the phenomena of viability. Viability and potential differences may, however, under certain conditions vary quite independently as evidenced by the fact that normal rates of migration are demonstrable after the cells have been killed by heat. Thus, considerable caution must be exercised in relating the existence of these charges to the metabolism of the cell.

SOME RELATIONS OF COMPOSITION TO SOLUBILITY OF ENAMELS IN ACIDES1

Review of literature.—The literature on acid resisting enamels and glasses is reviewed. Acid resisting powers produced by different oxides.—When substituted one for another, in each case in equal percentage amounts, various oxides and minerals increased the resistance of various enamels to the action of boiling 20 per cent hydrochloric acid in the following order of effectiveness: Al2O3, cryolite, Na2O, PbO, BaO, Li2O, MgO, CaF2, ZnO, SrO, CaO, B2O3. The first five mentioned were especially effective. The remainder are undesirable materials from the standpoint of acid resistance. Effect of the enamel base.—The relative effects of the materials were the same for various base enamel compositions. Effect of ZrO2 and TiO2.—ZrO2 and TiO2, when substituted for small amounts of SiO2, increased the resistance of various enamels to attack by acids, ZrO2 being most effective in this respect. The favorable action of ZrO2, is offset by a tendency to produce excessive chipping. Rutile gives less chipping than either zirconia or silica and greater acid resistance than silica. Best compositions.—Enamels 2,17,19,26,27, and 33 of table 1 showed resistance to action of the acid equivalent to that of the original competitions based on the analysis of a French acid-resisting enamel. By use of the data developed in this investigation other highly acid-resisting compositions can readily be formulated.

THE ISOELECTRIC POINTS OF THE PROTEINS IN CERTAIN VEGETABLE JUICES

The state in which a protein substance exists depends upon the nature of its combination with acids or bases and is changed by change in the protein compound. The nature of the compound of a protein that exists at any hydrogen ion concentration can be ascertained if the isoelectric point of the protein is known. Accordingly information regarding the isoelectric points of vegetable proteins is of importance for operations in which it may be desirable to change the state of protein substances, as in the dehydration of vegetables. The Protein in Potato Juice.-The hydrogen ion concentration of the filtered juice of the potato is in the neighborhood of 10(-7)N. Such juice contains the globulin tuberin to the extent of from 1 to 2 per cent. The character of the compound of tuberin that exists in nature was suggested by its anodic migration in an electric field. The addition of acid to potato juice dissociated this compound and liberated tuberin at its isoelectric point. The isoelectric point of tuberin coincided with a slightly lower hydrogen ion concentration than 10(-4)N. At that reaction it existed most nearly uncombined. The flow of current during cataphoresis was greatest in the neighborhood of the isoelectric point. This evidence supplements that of the direction of the migration of tuberin, since it also suggests the existence of the greatest number of uncombined ions near this point. At acidities greater than the isoelectric point tuberin combined with acid. The compound that was formed contained nearly three times as much acid as was needed to dissociate the tuberin compound that existed in nature. At such acidities tuberin migrated to the cathode. Though never completely precipitated tuberin was least soluble in the juice of the potato in the neighborhood of its isoelectric point. Both the compounds of tuberin with acids and with bases were more soluble in the juice than was uncombined tuberin. The nature of the slight precipitate that separated when potato juice was made slightly alkaline was not determined. The Protein in Carrot Juice.-The isoelectric point of the protein in carrot juice coincided with that of tuberin. Remarkably similar also were the properties of carrot juice and the juice of the potato. Existing in nature at nearly the same reaction they combined with acids and bases to nearly the same extent and showed minima in solubility at the same hydrogen ion concentrations. The greatest difference in behavior concerned the alkaline precipitate which, in the carrot, was nearly as great as the acid precipitate. The Protein in Tomato Juice.-The protein of the tomato existed in a precipitated form near its isoelectric point. Accordingly it was not present to any extent in filtered tomato juice. If, however, the considerable acidity at which the tomato exists was neutralized the protein dissolved and was filterable. It then migrated to the anode in an electric field. The addition of sufficient acid to make the hydrogen ion concentration slightly greater than 10(-5)N again precipitated the protein at its isoelectric point. At greater acidities migration was cathodic.

STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA

STUDIES IN THE PHYSIOLOGY OF SPERMATOZOA

Some soils of the Southern Island of New Zealand with special reference to their lime requirements

1. The Hutchinson-MacLennan method for determining the lime requirements of soils, when practised under suitable standard conditions, gives more reliable indications than are obtainable by the ordinary methods of chemical analysis.2. The method gives indications which appear to be uniformly in excess of the actual requirement of the soil for lime as judged by economic standards: hence a correcting value seems advisable.3. The correcting value for the soils of Canterbury Plains is about 0·10%.4. The greater acidity and higher lime requirement of soils of the Southland Plains appears to be due to a combination of lack of natural under-drainage and high rainfall, which prevents aeration and oxidation of organic matter, so that “sour” humus accumulates in the soil.