530 poisons : their effects and detection. [§§ 698-700. 
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 pro¬ 
duce symptoms of illness. In dogs there are paralysis, convulsions, 
vomiting, and difficult breathing. 
NH.CHg 
§ 698. Methylguanidine, NHHC^ Methylguanidine has 
NH 2 
been isolated by Brieger from putrefying horse-flesh ; it has also been 
found in impure cultures in beef broth of Finkler and Prior’s Spirillum 
FinJcleri. Bocklisch isolated it, working with Brieger’s process, from the 
mercuric chloride precipitate, after removal of the mercury and concen¬ 
tration of the filtrate, by adding a solution of sodium picrate. The pre¬ 
cipitate contained the picrate of cadaverine, creatinine, and methyl¬ 
guanidine ; 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, C 2 H 7 N 3 HC1.AuC1 3 (Au = 47*7 per 
cent.), forms rhombic crystals easily soluble in alcohol and ether ; 
melting-point 198°. The hydrochloride, C 2 H 7 N 3 HC1, crystallises in 
needles insoluble in alcohol. The picrate, C 2 H 7 N 3 C 6 H 2 (N0 2 ) 3 0H, 
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. 
. 
§ 699. Saprine, C 5 H 14 N 2 .—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 ^ives a crystal¬ 
line aurochloride, saprine does not; the platinum salt is also more 
soluble in water than the cadaverine salt. It is not poisonous. 
§ 700. The Choline Group. —The choline group consists of choline, 
neurine, betaine, and muscarine. 
