taste is less bitter than that of the z-salts. Both give Pettenkofer's reaction. The cholic acid from both has the same properties. The nitrogen of the two acids is about equal in amount. The carbon is rather less in the B-acid than in the a-acid; but on account of the difficulty of crystallising the compounds of the B-acid, it is not easy to make trustworthy analyses. W. D. H.

Physiological Chemistry.

Absorption in the Stomach of the Horse. By H. GOLDSCHMIDT (Zeit. physiol. Chem., 11, 421-437).-The amount of absorption which takes place from the stomach is difficult to estimate accurately, especially because it is difficult to make allowance for the composition and particularly for the proteïd constituents of the various digestive juices. The result can only be taken as comparative, and not absolutely correct. The general method of the analysis may be seen from the following example:-Horse killed 1 hours after food; the stomach contained 120 17 grams of cellulose, which correspond with 1442.6 grams of oats which contain 142.24 grams of proteid and 924-562 grams of constituents free from nitrogen, and about 200 grams of water. In the stomach, 3200 grams of juice was present which, deducting the 200 grams of water in the oats, leaves 3000 grams as the weight of saliva and gastric juice; 3000 grams of saliva contain 0.548 per cent. of proteïd-that is about 164 grams in all. In the stomach, the analysis of the contents gave the following results :

Eight similar investigations were made in which the general results may be tabulated as follows:

Percentage of non-nitrogenous substances absorbed. 16 13

9.

12

61

51

In the horses numbered 1, 4, 7, absorption was great; and in those numbered 3, 5, 6, 8, and 9, not so marked: this corresponds with the activity of digestion in the individual cases. The greatest part of the digested non-nitrogenous stuffs and an important part of the nitrogenous are absorbed during and after the sixth hour after food.

On account of the difficulty in these estimations arising from the want of knowledge concerning the composition of the digestive juices, some analyses were made to serve as data on which to correct the first series of observations; the various juices in the stomach, the duodenum, the middle of the small intestine, the ileum, the cæcum, the ventral colon, and the dorsal colon were investigated in two horses A and B. The percentages of proteïds were as follow:

:

The following conclusions are drawn :

1. That the intestinal juice becomes poorer in proteïds, non-nitrogenous constituents, total solids, and ash towards its ileal end.

2. That the amount of water correspondingly increases.

3. That the proteïds throughout are present in important quantities.

Somewhat similar investigations by Ellenberger and Hofmeister (Archiv. f. prakt. u. Wissensh. Thierheilkunde, 10, 328) in three horses gave an average result closely corresponding with that obtained in horse A. W. D. H.

Digestion and Digestive Secretions of the Horse. By ELLENBERGER and HOFMEISTER (Bied. Centr., 1887, 229-232).—This is a review of the long researches of the authors on this subject, of which many abstracts have been given in this Journal, and in the course of which many interesting particulars relating to the digestion of vegetable substances by men and animals have been treated,

The action of saliva in the process of mastication is shown to be more mechanical than chemical. The quantity of saliva used depends on the dryness and roughness of the food rather than its contents in starch, and the authors think that the chemical activity of saliva owes much to spores, which floating in the atmosphere, mix with the food and assist in the fermentation process.

A digestive action of the mixed food takes place in the stomach when the acidity due to hydrochloric or lactic acid does not exceed 0.03 to 0.04 per cent. The left section of the stomach of the horse does not secrete a gastric juice, this is the function of the right portion. The pure gastric fluid of the horse contains lactic, fatty, and amylaceous ferments, the latter in small quantities.

Cellulose is not digested in the stomach of the horse, but muscle, fat, gelatin, and flesh generally are easily digested, bone and elastic tissues more slowly. Pepsin operates actively only when acids are present, about 2 per cent. of lactic acid or 0.2 per cent. of hydrochloric acid being necessary; the activity of pepsin does not increase in proportion to its quantity after reaching a certain point, but it rather becomes injurious.

The acid which appears first in the digestive process is lactic acid and later hydrochloric; at the time of greatest activity, lactic acid is present in the upper and lower extremities of the digestive tract, hydrochloric acid being found in the intervening part.

The digestion of starch in the stomach of the horse lasts for about two hours, that of albuminous matter takes place later, and occupies three or four hours after the eating of the food; the drinking of water immediately after food does not appear to hinder digestion.

The secretions of the intestinal canal unite in themselves all the properties of the gastric juice, and can act as a substitute for it, and are particularly energetic in the decomposition of fats.

The duration of the digestive process in the horse is long, lasting almost three days.

A very active lactic fermentation of sugar takes place in the stomach and intestines, but the authors do not say that all the sugar which is lost in the course of passage is lost in that way, it is more probably reabsorbed.

J. F.

Changes in Milk produced by Freezing. By KAISER and SCHMIEDER (Bied. Centr., 1887, 267-269).—The matter is of importance to milk dealers in cold countries, where the contents of their cans become frozen.

Two samples were experimented with, one was frozen slowly, the other quickly, and afterwards partially thawed, in the former case the ice contained the greater part of the fat and the fluid portion most of the caseïn, milk-sugar, and salts.

In the quickly frozen and partially thawed sample, the fat was equally distributed between the solid and fluid portions; the author explains this by the fat globules rising to the top when the process of freezing is gradual, they thus become imbedded in the flakes of ice, whilst in quickly frozen samples this cannot take place, and the fat is more evenly distributed.

If a dealer whose milk has been frozen pours off the clear fluid which underlies the ice, he is liable to the suspicion of adulteration on the one hand, or will deliver milk above the standard on the other. Milk which has been frozen should be well thawed and shaken up, and not sold whilst any ice is visible. J. F.

Frozen Milk. By O. HENZOLD (Bied. Centr., 1887, 269-270).— The experiment shows different results, as in the quickly frozen sample, the ice contained a much larger proportion of fat than the ice of the slowly frozen, but the modus operandi was different, as during the process of slow freezing the milk was frequently agitated.

J. F.

Chemistry of Vegetable Physiology and Agriculture.

Fermentation of Sugar by Elliptical Yeast. By E. CLAUDON and E. C. MORIN (Compt. rend., 104, 1109-1111).-The yeast was obtained from a white wine of Rouillac, and was purified by successive cultivations. Fermentation took place at a temperature of 18-20°, and foreign germs were excluded. On distillation, the product was separated into an alcoholic liquid, an acid liquid, and a residue consisting of glycol, glycerol, and non-volatile products. The products. from 100 kilos. of sugar were as follows

The proportion of propyl and isobutyl alcohols is unusually low, and amyl alcohol constitutes almost the whole of the higher alcohols. The bases usually present in fusel oils are absent, and so also are normal butyl alcohol and butyric acid, which were found by Ordonneau in brandy (Abstr., 1886, 436). C. H. B.

Formation of Nitrogen during Putrefaction. By A. EHREnberg (Zeit. physiol. Chem., 11, 438-471).-This research follows up the author's previous observations (this vol., p. 172), and is devoted to the question as to whether free nitrogen is formed during the processes of nitrification induced by low organisms. The apparatus previously described was used. Earth containing the necessary organisms was added to a 2 per cent. solution of ammonium chloride, to a mixture of calcium sulphate, calcium carbonate, and ammonium chloride, in the presence of pure oxygen, and to a mixture of peptone, sodium chloride, sodium phosphate, saltpetre, and cane-sugar, in the presence of carbonic anhydride; but in none of these instances was any nitrogen given off, nor was nitric acid formed. In other experiments, in which putrefactive processes were more intense, in which urine, fæces, blood, and other organic matter was used and in which there was formation of nitrates, free nitrogen was formed as well; the details of the several experiments are given. the absence of oxygen, and also in the presence of a large quantity of this gas, free nitrogen is not formed; in the first case, methane and carbonic anhydride, and in the latter case carbonic anhydride alone are the gaseous products. In cases where nitrates and free nitrogen are formed, there is also at first a formation of methane.

W. D. H.

In

Absorption of Aniline Colours by Living Cells. By W. PFEFFER (Ann. Agronom., 13, 176-179).-The author has worked with very dilute solutions (1 in 100,000 or 1,000,000) of methyleneblue, methyl-violet, Bismarck-brown, magenta, &c., with a view of throwing light on the accumulation of such substances as sugar, nitre, &c., in particular organs of plants. The results show that the protoplasmic layer of living cells behaves very differently towards these colouring matters under different circumstances. Some colours are absorbed, some are not; those which are absorbed generally accumulate in the cell sap; all colour the protoplasmic layer in traversing it, except methylene-blue. Arriving in the cell sap, the colouring matter may behave in three different ways; it may accumulate in solution, may form a precipitate, or may attach itself to a pre-formed substance, generally tannic acid. In dead cells, the colour is absorbed by the nucleus. J. M. H. M.

Presence of Choline in Germinating Plants. By E. SCHULZE (Zeit. physiol. Chem., 11, 365—372).—Employing Brieger's method for the separation of nitrogenous bases, it is possible to obtain choline from germinating pumpkin sprouts. The base was identified by its reactions, and by the characters and elementary composition of its aurochloride and platinochloride. The quantity present is very small; from a kilogram of the dried sprouts, only about 3 grams of the aurochloride was obtained. W. D. H.

Composition of Potatoes. By M. A. SCOVELL and A. E. MENke (Amer. Chem. J., 9, 103-107). The following numbers are the maxima and minima obtained in the analyses of 20 varieties of potatoes-Specific gravity, 1-0923-10731; dry substance, 22.9120-20; starch, 16·05—12·05; sugar, gum, &c., calculated as glucose, 1-49-074. The specific gravity cannot be used for calculating the percentage of starch. The addition of various fertilisers has no appreciable influence on the proportions of the various constituents. The albuminoïds are most readily acted on by dilute hydrochloric acid; the percentage of albuminoïds varied from 2:19 to 2·69, that of peptones from 0.0294 to 0.0418: tyrosine formed about 0·008 per cent.; leucine and asparagine were not estimated. H. B.

Effects of Deep or Shallow Sowing on Cereals. By E. STÖSSNER (Bied. Centr., 1887, 236-244).—The author has been making experiments in sowing the seeds of wheat, rye, barley, and oats at different depths, and gives a résumé of his conclusions, from which the following are selected :

:

The depth at which the seed is sown is of great importance, an improper depth reducing the weight of the crop sometimes by onehalf.

In loamy humous soils, both winter and summer wheat, rye, and oats should not be sown deeper than 4 cm., whilst summer barley will bear a covering of 10 cm. When a large yield of straw is desired, the seed may be planted at a greater depth than when the heaviest grain crop is desired. In good soil, well pulverised and rolled, the