284 CHEMISTRY OF THE PTOMAINS. 



substance is formed by the action of bacteria upon a previously non- 

 poisonous base (see page 290). According to Lossen, guanidin is 

 formed, though in small quantity, in the oxidation of albumin. 



Fischer (1897) obtained this base by oxidizing 1-7 di-methyl 

 guanin whereas 7 methyl guanin gave only guanidin. It would 

 appear from this that the purin antecedent may constitute a sourc« 

 of methyl guanidin and even of creatinin. The hexon base arginin 

 (which see) contains a guanidin group and either it or a related 

 body may likewise share in the production of these bodies. 



The formulas of these closely related substances are here given for 

 comparison : 



GnAKIDIN. Ukea. 



NH = C< 0=C< 



Methyl GnANiDiN. Methyl TTbsa. 



.NH.CH. /NHCHj 



NH = C< = C< 



CESATiinif. Methyl Hydantodj. 



\NH — CO ^NH — CO 



Creatin. Methyl Hydahtoic Acid. 



/N(CHj).CHj,.COjH /N(CH,).CHj.CO,H 



NH = C<; = C< 



Methyl guanidin forms a colorless, easily deliquescent mass pos- 

 sessing a strong alkaline reaction. On heating with potassium 

 hydrate it decomposes and yields ammonia and methylamin. It is 

 a highly poisonous base. 



The hydrochlorid, CjHjNj.HCl, can be obtained from the picrate 

 by dissolving the latter in water acidulated with hydrochloric acid, 

 and extracting the solution with ether to remove the picric acid. 

 The colorless aqueous solution now on evaporation yields a thin 

 syrup which crystallizes in vacuum to compact prisms. These are 

 insoluble in alcohol, and give with platinum chlorid a double salt of 

 monoclinic needles (Haushofer) which are very easily soluble (1 part 

 in about 7 parts of water, Tatarinow). 



The aurochlorid, CjHjNj.HCl.AuClj (An = 47.71 per cent.), forms 

 rhombic crystals (Haushofer) which are easily soluble in ether, more 

 difficultly in water or alcohol ; readily soluble (Brieger). It readily 

 decomposes on heating in pure water, but may be crystallized from 

 water acidulated with hydrochloric acid. It melts at 198°. 



The picrate, C2HyN3.C,H2(N02)30H, comes down at first as a 

 resinous precipitate, which when boiled with much water solidifies in 

 the form of felted needles. It is very difficultly soluble in water, 



