Weak Hydrochloric Acid Research Articles

A Note on the Estimation of the Uric Acid Radical in Avian Excreta

EXPERIMENTS carried out on digestibility trials with poultry are complicated by the fact that the dung and urine are voided together and cannot be conveniently separated by mechanical means. It is the general practice to calculate the amounts of urinary substances present in the mixed excreta by estimating the uric acid and ammonia and then applying certain factors.The estimation of uric acid in avian excreta has engaged the attention of a number of workers in the field of poultry nutrition, and of the more recent methods evolved are those described by Hutchinson (1941), Bose (1944) and Bose and Ghosh (1945). Hutchinson extracted the dry faeces with hot lithium carbonate solution, placing over a water bath for fifteen minutes, and precipitated the uric acid from the filtered extract by means of the Benedict and Hitchcock (1915) ammoniacal silver magnesium precipitant. He decomposed the precipitate with a weak hydrochloric acid solution .

Resistance of Nickel-Containing Alloys to Corrosives Encountered in the Petroleum Refineries

Abstract Production of bulk gasoline in a modern petroleum refinery is accompanied by corrosion during topping and cracking from sulphur and from weak hydrochloric acid which is formed from salts in the crude. Organic acids such as naphthenics are also often present and are quite corrosive. Solutions of refinery corrosion problems are considered in this paper.

Societies and Academies

LONDON. Royal Society, February 7.—G. Udny Yule: A mathematical theory of evolution based on the conclusions of Dr. F. C. Willis, F-.R.S. The fundamental assumptions are that: (i) Within any species, in any interval of time, an “accident “may happen that brings about “specific mutation,” i.e. the throwing of a new form, regarded as a new species within the same genus; (2) within any genus, in any interval of time, an “accident “may happen that brings about “generic mutation,” i.e. the throwing of a new form so different from the parent that it will be placed in a new genus. Both chances are taken as invariable within, the group considered and constant for all time. Sections I.—III. of the paper lead up to the expression for frequency-distribution of size of genus at any given time. In Section IV. the expression is tested on data for four cases, and gives very good agreement with facts, but there are serious difficulties of interpretation. In Section V., frequency-distributions of age for genera of a given size are determined. Approximately for large genera after infinite time, the mean age varies as the logarithm of the number of species, but the dispersion is considerable. When time is limited, primordial and derived genera form distinct groups. Finally in Section VI. an attempt is made to estimate the doubling period for species in flowering plants, which is placed at probably some two or three million years, the present rate of production of specific mutations probably lying between i in 15 and I in 30 years, among all flowering plants on the whole surface of the globe.—L. B. Winter and W. Smith: Studies on carbohydrate metabolism. I. Variations in the nature of the blood sugar. Marked differences exist between the blood sugar of normal persons and those suffering from diabetes mellitus. The sugar was extracted from considerable quantities of blood and a comparison made between the observed optical rotation (P) and that calculated from the reducing power of the carbohydrate, on the basis that glucose is the only reducing substance present (C). In diabetic cases, P is usually greater than C, and is increased by mild hydrolysis with weak hydrochloric acid, whereas C is unaltered. This may be evidence for the existence of complex sugars in diabetic blood. Similar substances are present in the blood of rabbits after injection of either adrenaline or thyroid alone. Injection of thyroid and adrenaline together usually causes an increase in the total blood sugar, but no change from the normal; P is low and complex sugars are absent. After injection, of insulin into rabbits the blood sugar is dextro-rotary, but has no copper reducing power. Insulin convulsions in rabbits are relieved by adrenaline alone or by a mixture of thyroid and adrenaline.—J. W. Pickering and J. A. Hewitt: The action of “peptone “and of nucleic acids on the coagulability of the blood. Intravascular injection of Witte's “peptone “into tortoises deprived of hepatic activity inhibits coagulation of blood subsequently shed. Addition of moderate concentrations of “peptone “to blood of the tortoise in vitro causes prolonged inhibition of clotting, provided the blood has not been in contact with damaged tissues. As regards rats, partly pigmented animals are more resistant to the anticoagulant action of peptone and to its toxic effect on the heart than are animals with completely pigmented fur. Albino rats are still more resistant. The rapid intravascular injection or addition in vitro of thymus or yeast nucleic acids inhibits coagulation of blood shed from, cats and rats which have been deprived of hepatic activity. Serial intra-vascular injections of thymus nucleic acid into cats or rats deprived of hepatic activity produce hyper-coagulability followed by tolerance, culminating in immunity to the anticoagulant action of nucleic acid. Immunisation can be produced with material free from protein. Anticoagulant action of thymus nucleic acid is exhibited during the presence and absence of platelets. It is suggested that nucleic acid inhibits clotting by union with plasma components, forming a more stable complex than that existent in normal circulating blood.—E. C. Grey: The latent fermenting powers of bacteria. Pts. I., II., and III. There cannot be a host of essentially different anzymes. The mechanism by which succinic acid is split into two parts cannot differ fundamentally from the mechanism by which glucose is split into two parts to form lactic acid, or three parts to form acetic acid, or into two parts to form a mixture of succinic acid and acetic acid or alcohol. It is not conceivable that the addition of formates can change one enzyme into another, as the lactic-acid-forming enzyme into an acetic-acid-forming enzyme, unless both have a common basis.

ORGANIC MATTER IN THE EXPIRED BREATH WITH ESPECIAL REFERENCE TO ITS INHIBITING POWER ON OXIDIZING FERMENTS

Weichardt claims to have demonstrated the presence of an organic body in the expired air. He allowed the exhaled breath to pass through hydrochloric acid solution, evaporated the resulting solution to dryness on a water bath, and obtained a weighable residue which charred on ignition. If he neutralized the acid solution and concentrated it under reduced pressure, he obtained a solution which inhibited the bluing of the guaiacum indicator by blood. By exposing calcium chloride in a room in which the air had been vitiated, he claimed also to have obtained a substance from the air which prevented the bluing of the guaiacum indicator by blood. The experiments here recorded show that a variable amount of matter is retained by weak hydrochloric solution when exhaled breath is passed through it, and that this matter is volatile on ignition. Contrary to the findings of Weichardt, there is no charring or blackening. Nesslerization shows the residue to consist mainly, if not wholly, of ammonium chloride. This ammonia is believed to have come from the decomposition of food particles about the teeth. In one case the person (S.) had smoked just before the experiment, so that a small amount of the ammonia from the tobacco smoke may have been held temporarily by the saliva and food particles in the mouth and been given off gradually during the experiment. Weichardt's experiments on the inhibition of the guaiacum test for blood by means of the substances retained when exhaled breath is passed through hydrochloric acid or over calcium chloride crystals are not corroborated. It is further shown that the guaiacum indicator is unreliable for these tests in view of the fact that a small amount of free acid or free alkali will inhibit the guaiacum test for blood. This fact is offered as a probable explanation of Weichardt's results. Calcium chloride alone gives a deep blue color with the guaiacin indicator. Weichardt used this salt to collect from the expired breath certain unknown substances which he claims inhibit the oxidation of guaiacum by blood. His results are therefore inconclusive. The phenolphthalin test for blood has been studied in this connection and further light has been thrown on this reaction. The sodium salt of phenolphthalin is colorless in alkaline solution, and is readily oxidized by minute quantities of blood to phenolphthalein which gives a characteristic deep purplish red color in alkaline solution. It has been found that the presence of calcium chloride and ammonium chloride in small amounts retards and, in large amounts, prevents this reaction. It is believed that any salt composed of a weak base combined with a strong acid will have the same effect. This is discussed in the text. It has also been shown that the presence of calcium chloride or ammonium chloride decreases the depth of color of phenolphthalein in sodium hydroxide solution. Carbon dioxide also prevents the oxidation of phenolphthalin by blood. Of course this does not mean that carbon dioxide prevents the action of the oxidizing ferments generally. In this particular case the substance to be oxidized, namely phenolphthalin, was not allowed by reason of the presence of the carbon dioxide to combine with the alkali and thereby assume a state in which it could be easily oxidized. The results of one experiment seem to indicate a relation between the amount of dissolved oxygen in the solutions and the percentage of oxidation. Sodium chloride either alone or with the aid of hydrogen peroxide is able to bring about the oxidation of phenolphthalin in alkali to a very slight extent (3.5 to 5 per cent. in twenty-four hours). Therefore phenolphthalin as a test for oxidizing ferments should not be used in the presence of an appreciable amount of inorganic salts or carbon dioxide. Complete dialysis is recommended in these cases. It is also to be noted that the great delicacy of the test allows considerable dilution. Liquids were obtained from the expired breath by passing this through weak hydrochloric acid or by condensing the moisture in it by conducting it through cooled Drechsel bottles. Attempts were then made to prove the presence in these liquids of some substance which inhibits the oxidation of phenolphthalin by blood, but all were unsuccessful. Moreover attempts to concentrate these liquids by evaporation under reduced pressure or by the passage of a direct current (colloidal travel) were also unsuccessful. It is planned to improve upon the apparatus used to concentrate colloids by the passage of a direct current, and to test the effect of expired breath products on the rate of oxidation of phenolphthalin by blood.