Page images

Importance of Ammonia for the Formation of Glycogen in the Liver of the Rabbit. By F. RÖHMANN (Pflüger's Archiv, 39, 21-53).-Asparagine and glycocine given with a carbohydrate diet increase the amount of glycogen formed in the liver to a marked extent; this increase is more pronounced with asparagine than with glycocine. On account of its slight solubility, asparagine is probably not absorbed unchanged, but undergoes decomposition with formation of ammonia.

Ammonium carbonate given with the same diet increases the glycogen in a still more marked manner, but ammonia in the form of lactate seems to be inert.

As sodium carbonate and hydrogen carbonate have no effect, ammonium carbonate does not exert its influence by reason of its alkalinity.

As a possible explanation, the author suggests that the ammonia and a carbohydrate entering the liver cells together may form a new compound which will split into glycogen on the one hand and a nitrogenised product on the other, for instance, urea.

J. P. L.

Feeding and Development of Silkworms. By O. KELLNER (Landw. Versuchs-Stat., 1886, 381-392).-This article contains an account of experiments which are a continuation of those previously detailed (Abstr., 1884, 1202). The research was commenced with the view of determining what quantity of food was necessary for the full and healthy development of the worm, with the largest subsequent supply of silk. Without entering into the details of feeding, &c., all of which are fully given in tables, it will be sufficient to give the final results. Every increase of growth requires an increase in the food, but this increase in food is not commensurate with the growth, being very much higher; the weaker the insect is before envelopment, the greater will be the loss during metamorphosis, by respiration, &c.

A poorly fed and developed caterpillar produces a lower yield of valuable silk than those which are well and largely fed, and will contain more nitrogenous and mineral matter, whilst the well-fed insect will be richer in fat and other non-nitrogenous matter. E. W. P.

Isethionic Acid in the Body, and Thiosulphuric Acid in the Urine. By E. SALKOWSKI (Pflüger's Archiv, 39, 209-222).-In a former paper (Virchow's Archiv, 66, 315), the author stated that in the dog the administration of sodium isethionate produced an increase of sulphuric acid in the urine, but that thiosulphuric acid was under all circumstances absent. Heffter (Pflüger's Archiv, 38, 476) states however, that sulphuric acid is not formed from isethionic acid, but that the greater part (78 per cent.) of the latter acid leaves the body as thiosulphuric acid, and a smaller portion (22 per cent.) in some undiscovered manner. Heffter himself explains the discrepancy by supposing it to be due to the difference in diet during the investigation, Heffter using meat, not bread and milk as in Salkowski's earlier experiments.

The present research is a reinvestigation of the subject: a dog was

fed on a fixed meat diet, and for three days 3 grams of sodium isethonate was given per diem. The results are shown in the following:


[blocks in formation]

This table shows that whereas the nitrogen output remains constant, the amount of sulphates is increased; the increase could there-fore not have been due to increased metabolism of proteïds; it is therefore all due to the isethionic acid, and it is found from the foregoing numbers, that 30 per cent. of the isethionic acid must have become oxidised into sulphuric acid. By comparing the intensity of the sulphuretted hydrogen reaction, it was found also that the amount of thiosulphuric acid in the urine was slightly increased. The amount of this acid in the urine was estimated also by its reducing action on potassium permanganate; the increase during the days when the drug was given, show theoretically that 134 per cent. of the sulphur of the isethionic acid pass out of the body in the form of thiosulphuric acid, a figure which is shown by control experiments to be too high, as the urine contains other easily oxidisable substances. The question as to what becomes of the remainder of the sulphur is not entered into. There seems also to be no way of reconciling the present results with those obtained by Heffter. The aromatic sulphonic acids pass out unchanged in the urine, no thiosulphates being formed; this also is contradictory to the statements of Heffter. W. D. H.

Trypsin in Urine. By H. LEO (Pflüger's Archiv, 39, 246264). Since the publication of the author's paper (Abstr., 1886, 381) in which he showed that trypsin did not exist in the urine, Gehrig (Pflüger's Archiv, 38, 35) states he has found trypsin in the urine; pieces of fibrin stained with magdala-red, soaked in urine, and transferred to 1 per cent. soda solution undergo digestion in a few hours; this cannot be due to putrefaction as it is so rapid; it is however prevented by the admixture of thymol with the digesting mixture; this is explained by saying that thymol hinders pancreatic digestion. The present research is a reinvestigation of the subject, the urine of healthy men and dogs being employed. It is found that thymol does not hinder pancreatic digestion. A very weak solution of the tryptic ferment was prepared by adding a drop of glycerol extract of pancreas to a litre of water. This excited no digestive action on fibrin. After pieces of fibrin had been soaked in it for

24 hours, however, and then transferred to a 1 per cent. soda solution they underwent digestion, as they had absorbed the ferment. With the urine, however, no such result ever occurred; that is, urine, if it contains trypsin at all, contains a less amount than the weak solution of it obtained by adding a drop of extract of pancreas to a litre of water. W. D. H

Chemistry of Vegetable Physiology and Agriculture.

The Bacillus of Panary Fermentation. By E. LAURENT (Bied. Centr., 1886, 648).—The author says that the surface of wheat, rye, and other food grains contains spores of bacilli which in grinding pass into the flour, and when made into dough they germinate, evolve carbonic anhydride, and raise the bread. When cultivated on gelatin, it develops characteristic cultures different from other bacilli, and has been given the name of Bacillus panificans; it exists with or without oxygen, and renders albumin and gluten soluble; it also grows in saccharose and in a weak solution of boiled starch; it withstands the heat of boiling water, if at a depth of 7 or 8 mm. in the bread; it is abundant in bread which has been eaten, and is found freely in the fæces. It can attack starch after baking, if the medium is not sufficiently acid, and causes a disease in bread which the author has often observed, and calls viscid or clammy bread; the addition of a sufficient quantity of an organic acid prevents this.

J. F.

Decomposition of Silicic Acid by Leaves. By A. DENARO (Gazzetta, 16, 328-330).-A few years ago Grimaldi stated in a pamphlet that silica is decomposed by leaves exposed to sunlight, precisely as carbonic anhydride is, into the element and oxygen. It is probable, however, that sufficient care was not taken to exclude carbonic anhydride derived from the potassium carbonate, as an impurity in the silica. Accordingly the author has repeated the experiments with a sample of silicic acid obtained from a sodium silicate produced by the direct fusion of sodium oxide with silica. Comparative experiments were made with leaves of which some were previously deprived of air, whilst others were introduced directly into the solution of silicic acid. In the former case, no oxygen was evolved, in the latter only a small quantity. Further, it is shown that no silica is absorbed by the leaves; the proportion of silica in them was found to be the same, whether or not they had been treated by the silicic acid solution. V. H. V.

Formation of Albuminoïds in Plants. By C. O. MÜLLER (Landw. Versuchs-Stat., 1886, 226-335).-From the experiments which have been made on many plants, it would appear that under normal conditions, plants contain asparagine, and this amide appears

if the growing parts are placed in darkness; but in fully grown portions, asparagine is only exceptionally found, and then only in traces. If a portion of a plant is placed in darkness, by enveloping it in black paper, whereby it still remains connected with the parent, and the older portions are left undisturbed, then an accumulation of asparagine is formed, which when the light is admitted, is absorbed ; This does not occur in the fully grown parts, save exceptionally. This result seems to show that the formation of asparagine is independent of carbohydrates, and also that the amide formed is not a bye-product of the interchange of matter within the plant. It has also been found that even when a plant is growing under abnormal conditions, when all carbonic anhydride has been removed from the air, asparagine is formed in the young parts, but not in the matured portions. Consequently it appears as if light played as inconspicuous a part in the formation of asparagine as carbohydrates. The author considers that asparagine is formed by the union of inorganic nitrogen compounds and malic acid within the plant, the acid being derived from the carbohydrates. E. W. P.

Observations on the Growth of Potatoes. By U. KREUSLER (Bied. Centr., 1886, 618-624).-The author has examined potatoes at different stages of their growth. At the time of sowing, large and small tubers were of the same specific gravity and composition; taken up shortly after the sowing, there was but little change observable, there was more moisture, due to partial exhaustion of their substance. Glucose was not found before planting, but was present in the germinating tubers; nitrogenous combinations diminished considerably in the growing roots.

The young tubers gradually developed dry matter, principally starch, in proportion as they grew. Glucose was present at the beginning, but gradually decreased as they ripened, when it disappeared. Substances which reduced copper were absent from the very young plants, but appeared at a later stage to disappear when fully ripe; the amount of carbohydrates in the sap was twice as much in the young as in the ripe tubers.

In the stalks and leaves, cellulose and non-nitrogenous extract increased, raw protein and fat decreased; the fruit is tolerably rich in fat; the whole young foliage of the potato belongs to those vegetables which are richest in nitrogen, the proportion of the dry substance amounting to 7.5 per cent. = 47 per cent. crude proteïn; the amount of nitrates in the non-proteïn portions is also very considerable, in the whole plant 3.5 per cent., in the stalks 5 per cent., calculated as N205. This large quantity of nitrates leads the author to agree with André, Berthelot, and Schulze, that it is not altogether supplied from external sources, but that a part is formed in the plant itself. J. F.

Ammonia in Beetroots. By L. BATTUT (Bied. Centr., 1886, 604 -607). The opinions of persons who interest themselves in this matter are divided, some asserting the presence of ammonia in the roots, others the contrary. Owing to the rapid decomposition of the organic constituents of beet-juice when heated with alkalis, the deter

minations were made in the cold by Schlösing's method-in each of four dishes 100 c.c. of distilled water was poured, in one normal beetjuice with 10 c.c. milk of lime, in two others milk of lime with two kinds of ammonium salts, the fourth milk of lime only-the dishes covered with glass plates to which were fixed moistened test-papers; the three gave an immediate alkaline reaction. Attempts at quantitative estimations were made without much success, but the author concludes from their results that an ammoniacal salt exists in the roots which is readily decomposed by caustic magnesia, and that there are two nitrogenous organic substances present, one, probably asparagine, quickly decomposed by lime, the other by caustic potash solution. J. F.

Milky Juice of Certain Euphorbiaceae. By G. HENKE (Arch. Pharm. [3], 24, 729-759).-Hitherto euphorbone had not been obtained in a pure state, even Flückiger, who proposed the name, was unsuccessful. The author treated finely powdered euphorbium in the cold with light petroleum of 60-70° boiling point; this treatment being repeated as long as anything was dissolved. The solutions obtained were mixed, filtered, and allowed to evaporate spontaneously. The sides of the evaporating vessel became coated with beautiful, transparent, crystalline needles of euphorbone, whilst the remainder of the residue consisted of a yellowish, crystalline, warty mass. Repeated treatment with light petroleum gives a pure product finally, but is wasteful; it is better to dissolve the yellow mass in ether after removing the petroleum by heating on the water-bath; on adding alcohol until a faint turbidity appears, filtering and allowing to remain, a yellow, resinous mass separates. The liquid on evaporation leaves a snow-white, butter-like mass which gives brilliant needles on crystallising from a sufficiently dilute solution of light petroleum. Euphorbone thus prepared melts at 67-68°, its composition was found to be C20H36O. Its rotatory power dissolved in chloroform was [x]D D = +15-88°. Its crystals are persistent in the air, tasteless, and are neutral in solution. It is very soluble in light petroleum, chloroform, ether, alcohol, benzene, acetone, and 90° vol. per cent. alcohol, less soluble in more dilute alcohol. It is unaffected by dilute acids, sodium carbonate, ammonia, potash, and soda, and by alcoholic zinc chloride solution. It is soluble in 10,000 parts of hot water. Cold anhydrous acetic acid does not affect it; when heated at 150-200° a solution is obtained from which a yellowish precipitate is thrown down on diluting with much water, this precipitate has the properties of unchanged euphorbone. Bromine acts violently on the compound, producing a yellow, resin-like, non-crystallisable mass. Hot nitric acid ssolves euphorbone, and from the solution an amorphous, nitrogenous compound can be obtained. A granular oxidation product was obtained by long boiling with potassium dichromate and sulphuric acid. On heating euphorbone with phosphoric anhydride, heptane, octane, xylene and small quantities of other aromatic hydrocarbons were obtained. The residue from the preparation of euphorbone, when extracted with alcohol, yielded two resins, one soluble and the other insoluble in ether; their reactions are detailed. The detection of malic acid, gum, and other substances in the residue and the extrac

« PreviousContinue »