The hydrochloride crystallises in tetrahedra; the aurochloride crystallises in cubes (Au=41·66 per cent.). Its melting-point is 182°.
§ 683. Tyrotoxicon (Diazobenzol, C6H5N2(OH)).—It appears, from the researches of Vaughan and others, that diazobenzol is liable to be formed in milk and milk products, especially in summer time. It is confidently asserted by many that the summer diarrhœa of infants is due to this toxine; however that may be, it is well established that diazobenzol is a violent poison, causing sickness, diarrhœa, and, in large doses, an acute malady scarcely distinguishable from cholera, and which may end fatally. There will always be difficulty in detecting it, because of its instability. The following is the best process of extraction from milk. The milk will probably be acid from decomposition; if so, the whey must be separated by dilution and filtration; without dilution it may be found impracticable to get a clear filtrate. In order to keep the bulk down, 25 c.c. of the milk may be diluted up to 100 c.c., and, having obtained a clear filtrate from this 25 c.c. thus diluted, the filtrate is used to dilute another 25 c.c. of milk and so on. The acid filtrate is neutralised by sodium carbonate, agitated with an equal volume of ether, allowed to stand in a stoppered vessel for twenty-four hours, and the ether then separated and allowed to evaporate spontaneously. The residue is acidified with nitric acid and then treated with a saturated solution of potash, which forms a stable compound with diazobenzol, and the whole concentrated on the water-bath. On cooling, the tyrotoxicon compound forms six-sided plates. Before the whole of this process is undertaken, it is well to make a preliminary test of the milk as follows:—A little of the ether is allowed to evaporate spontaneously. Place on a porcelain slab two or three drops of a mixture of equal parts of sulphuric and carbolic acids, and add a few drops of the aqueous solution; if tyrotoxicon be present, a yellow to orange-red colour is produced. A similar colour is also produced by nitrates or nitrites, which are not likely to be present under the circumstances, milk having mere traces only of nitrates or nitrites; it may also be due to butyric acid, which, in a decomposed milk, may frequently be in solution. Therefore, if a colour occurs, this is not absolutely conclusive; if, however, no colour is produced, then it is certain that no diazobenzol has been separated. That is all that can be said, for the process itself is faulty, and only separates a fractional part of the whole.
§ 684. Toxines of Hog Cholera.—Toxines have been isolated by F. G. Novy[671] from a cultivation of Salmon’s bacillus in pork broth. The fluid possessed a strong alkaline reaction. For the isolation, Brieger’s method was used. The mercury chloride precipitate was amorphous and was converted into a chlorine-free platinum compound, to which was assigned the composition of C8H14N4PtO8. After separation of this compound, the mother liquor still contained a platinum salt crystallising in needles, and from this was obtained the chlorhydrate of a new base, to which was given the name of susotoxine; it had the composition of C10H26N22HCl,PtCl4. Susotoxine gives general alkaloidal reactions, and is very poisonous.
[671] Med. News, September 1890.
§ 685. Other Ptomaines.—Besides the ptomaines which have been already described, there are a number of others; the following may be mentioned: isoamylamine,[672] (CH3)2CH.CH2.CH2NH2; butylamine, CH3CH2CH2CH2NH2; dihydrolutidine,[673] C7H11N; hydrocollidine,[674] C8H13N; C10H15N (a base isolated by Guareschi and Mosso[675] from ox-fibrin in a state of putrefaction by Gautier’s method; it forms a crystalline hydrochloride and an insoluble platinochloride; its action is like that of curare but weaker); aselline,[676] C25H32N4, isolated from cod-liver oil; typhotoxine,[677] C7H17NO2, isolated from cultures of Eberth’s bacillus. So far as the published researches go, it would appear that other crystalline substances have been isolated from the urine, from the tissues, and from the secretions of patients suffering from various diseases; the quantity obtained in each case has, however, been, under the most favourable circumstances, less than a gramme; often only a few milligrms. To specifically declare that a few milligrms. of a substance is a new body, requires immense experience and great skill; and, even where those qualifications are present, this is too often impossible. This being so, the long list of named ptomaines, such as erysipeline, varioline, and others, must have their existence more fully confirmed by more than one observer before they can be accepted as separate entities.
[672] Hesse, Chem. Jahresb., 1857, 403.