[668] Pflüger’s Archiv, xii. 205.
The physiological effects of guanidine are as follows:—
A centigrm. of guanidine salt injected into the lymph sac in the back of frogs produces, after a few minutes, muscular convulsions: first, there are fibrillar twitchings of the muscles of the back; next, these spread generally so that the whole surface of the frog seems to be in a wave-like motion. Irritation of the limbs produces tetanus. There is, at the same time, increased secretion from the skin. The breathing is irregular. In large doses there is paralysis and death. The heart is found arrested in diastole. The fatal dose for a frog is 50 mgrms.; but 1 mgrm. will produce symptoms of illness. In dogs there is paralysis, convulsions, vomiting, and difficult breathing.
.—Methylguanidine has been isolated by Brieger from putrefying horse-flesh; it has also been found in impure cultures in beef broth of Finkler and Prior’s Vibrio proteus. Bocklisch isolated it, working with Brieger’s process, from the mercuric chloride precipitate, after removal of the mercury and concentration of the filtrate, by adding a solution of sodium picrate. The precipitate contained the picrates of cadaverine, creatinine, and methylguanidine; cadaverine picrate, insoluble in boiling absolute alcohol, was separated by filtering from a solution of the picrates of the bases in boiling absolute alcohol; the alcohol was evaporated from the filtrate and the residue taken up with water. From this aqueous solution the picric acid was removed and then the solution precipitated with gold chloride; methylguanidine was precipitated, while creatinine remained in solution.
Methylguanidine aurochloride, C2H7N3HCl.AuCl3 (Au = 47·7 per cent.), forms rhombic crystals easily soluble in alcohol and ether; melting-point 198°. The hydrochloride, C2H7N3HCl, crystallises in needles insoluble in alcohol. The picrate, C2H7N3C6H2(NO2)3OH, comes down at first as a resinous mass, but, after boiling in water, is found to be in the form of needles soluble in hot absolute alcohol; melting-point 192°. The symptoms produced by methylguanidine are rapid respiration, dilatation of the pupils, paralysis, and death, preceded by convulsions. The heart is found arrested in diastole.
§ 673. Saprine, C5H14N2.—Saprine is isomeric with cadaverine and neuridine; it was found by Brieger in human livers and spleens after three weeks’ putrefaction. Saprine occurs, in Brieger’s process, in the mercury precipitate. Its reactions are very similar to those of cadaverine; the main difference being that cadaverine hydrochloride gives a crystalline aurochloride, saprine does not; the platinum salt is also more soluble in water than the cadaverine salt. It is not poisonous.
§ 674. The Choline Group.—The choline group consists of choline, neurine, betaine, and muscarine.