THE ANALYST. 191 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Formation of Aldehydic or Ketonic Substances during Acetic Fermenta- tion, K. Farnsteiner. (Zeit. UnterszLch. Nuhr. Geizussm., 1908, 15, 321-326.)--All liquids which have undergone more or less complete acetic fermentation contain a192 THE ANALYST. neutral, volatile substance which reduces Fehling's solution. The copper reduction may in certain cases cause an apparent increase in the sugar percentage of 0.75 per cent., but the amount of the substance produced during the fermentation varies con- siderably, and bears no relation to the amounts of sugar, acetic acid, etc., present. The estimation of reducing sugars in vinegars and similar products should, therefore, be carried out on the partially evaporated sample. In its behaviour towards Fehling's solution and sulphurous acid the substance resembles acetol, which Kling (Compt.Rend., 1901, 133, 231) has shown to be the product of the action of Mycoderma aceti on glycol. I t differs from acetol in that its osazone melts at 243" C., whilst acetol osazone melts at 145" C. Besides the osazone, an oily substance is obtained when a solution of the substance is treated with phenylhydrazine. w. P. s. Changes in the Composition of the Body-Fat of Rabbits when the Animals are Fed or Inoculated with Cotton-seed Oil. K. Lendrieh. (Zeit. Untersuch. Nahr. Genussm., 1908, 15, 326-334.)-A number of experiments were carried out, in which five rabbits were fed with food containing cotton-seed meal, four with food mixed with cotton-seed oil, and five were inoculated every eight days with cotton-seed oil.Two rabbits were fed on ordinary food and served as a control. The experiments extended over a, period of from 21 to 402 days; in some cases the animals received ordinary food after the experimental period. The results of the examination of the fats'obtained from the rabbits show that continuous feeding with substances containing cotton-seed oil, although the daily quantities taken be small, has a retarding action on the deposition of the fat in the animal. The glycerides of the oil are deposited, and plainly alter the composition of the body-fat. After-feeding with other foods causes the gradual disappearance of the constituent which gives the reaction with Halphen's test, but the glycerides of the cotton-seed oil appear to remain for some time in the body-fat.Phytosterol was not detected with certainty in t,he fat of the animals fed with cotton-seed oil. When the rabbits were inoculated with the oil, the latter was absorbed rapidly, the presence of both the cotton-seed oil glycerides and phytosterol being detected in the body-fat. The latter also gave reactions with Halphen's test. w. P. s. The Cause of Poisoning by Arsenical Wall-Papers. B. Neppe. (Scienxa Pratica, 1908, 1, 82-84.)-1t has been found by Gosio that cases of poisoning by arsenical wall-papers are to be attributed, not, as commonly believed, to the dry dust given off by the paper, but to a volatile organic arsenic compound produced by the action of certain mould-fungi in the presence of carbohydrates (the paste by which the paper is attached to the wall).This action is strictly specific, and has only been found to be possessed by the following mould-fungi, arranged in the order of decreasing activity ; Penicilliuna brevicaule, Aspergillus clavatus, A . fumigatus, A . glaucus, A . virens, A . candidus, and Mwor mucedo. A certain degree of moisture is required, and it is stated that there is no risk of poisoning from an absolutely dry wall-paper. The optimum temperature for the action of the mould-fungi is about 25" C., and the process appears to be a direct vital phenomenon, and not due toTHE ANALYST. 193 diastatic action, Above a certain proportion of arsenic the mould-fungi themselves are poisoned, but they can gradually be rendered immune to larger quantities.The volatile organic compound was identified as diethyl arsine, H A ( C,H,),. When passed into a solution containing 8 to 12 per cent. of mercuric chloride and 20 per cent. of hydrochloric acid, it yielded the compound : /C&, + HgC4 H'As\C,H, + HgC1,. C. A. M. Iron Contents of Fats, Lipoids, and Waxes. W. Glikin. (Bey. dezbt. Chem Ges., 1908, 41, 910-915.)-Bone-rnarrow, purified by dissolving in ether and shaking with dilute acid, contains small quantities of iron. The iron contents of the fat are highest at the time of birth of the animal, and decrease from then onwards. Iron has been detected and estimated in fats other than bone fats, also in vegetable fats and various waxes. The iron exists in combination with the lecithin and cholesterol components of the fats, and purified samples of lecithin have shown as much as 0.5 per cent.of iron ; purified cholesterol may contain 0.06 per cent. In many cases the quantity of iron in the various fats was in constant proportion to the quantity of phosphoric acid in the ratio of Fe,O, to 3P,O,. J. F. B. Studies on Melanogenesis : The Action of Tyrosinase on Substances Similar to Tyrosine. G. Bertrand. (BzLZZ. SOC. Chim., 1908 [iv.], 4,335-343J-It is known that in the phenomenon of melanism-that is, the production of black pigment in vegetable or animal tissues-the oxidising enzyme, tyrosinase, plays an essential part. The blackening of the sugar in beetroots and in dahlia tubers, the coloration of brown bread, etc., ia due to this ferment, and in many cases the chromogen has been separated and identified. The results of experiments are now recorded, showing that tyrosinase has an oxidising effect on other substances than tyrosine, For instance, p-oxyphenylethylamine, p-oxyphenylamine, p-oxyphenyl- propionic acid, p-oxyphenyl-acetic acid, p-oxyphenyl-benzoic acid, p-creBo1, and phenol, are acted on by tyrosinase, the colorations obtained ranging from yellow to black. The dipeptide, glycyltyrosine, is readily oxidised in the presence of tyrosinase, the colour produced being red. On the contrary, phenylalanine, phenylethylamine, phenylaminoacetic acid, phenylacetic acid, alanine, glycocol, etc., do not give colorations when acted on by the ferment. w. P. s.