298 CHEMISTRY OF THE PTOMAJNS. 



same manner that it contains interchangeable acid radicals. This 

 view is supported not only in the case of beet-root, where cholin and 

 betain exist together, but the same two bases have been observed in 

 cotton-seed. A similar coexistence was observed in the toad-stool 

 (Agaricus muscarius), in which cholin and muscarin were found. 

 And, lastly, the same condition holds true probably for mytilotoxin 

 and betain, which were shown to be present together in poisonous 

 mussels. 



Lecithin cannot always be regarded as the source of cholin in 

 plants, since this base is known to occur as a glucosid in the seeds 

 of white mustard. The sinapin decomposes according to the equa- 



C„Hj,N05 + 2H,0 = QHisNO, + C„H, A- 

 SiNApm. Cholin. Sihapic Acid. 



According to Schulze (1891), the cholin which is isolated from 

 pea- and vetch-seeds exists preformed in the seeds and does not re- 

 sult from lecithin by the process of extraction. This is also proba- 

 bly true with reference to cotton-seed cake. The condition in which 

 betain exists is not determined. 



Decompositions of Cholin. — Baeyer (1866) succeeded in con- 

 verting cholin into neurin by a purely chemical process. This was 

 accomplished by heating cholin chlorid with concentrated hydriodic 

 acid and red phosphorus in a sealed tube at 120°-150°, whereby the 

 compound CjHjjNIj was formed. Fuming hydrobromic acid heated 

 to 160°— 170° may also be employed. The iod-iodid of cholin thus 

 obtained, on treatment with moist silver oxid (page 290), gave a 

 base, the platinochlorid of which corresponded to the formula 

 (CjH,2NCl)2PtCl^ -I- H^O. This double salt, according to Baeyer, 

 is readily soluble in water and gives reactions similar to cholin. 

 Although Baeyer is emphatic in his assertion that this is the vinyl 

 compound (neurin) formed from the oxyethyl base (cholin), yet it 

 seems that there is room for doubt in regard to the interpretation 

 of his results. Thus neurin platinochlorid is difficultly soluble in 

 water, contrary to the behavior of the platinochlorid obtained by 

 him. On the other hand, cholin platinochlorid is easily soluble in 

 water, and it would seem, therefore, that Baeyer has not converted 

 cholin into neurin, but rather has regenerated cholin from its iod- 

 iodid. If such were the case, we would expect that the iod-iodid of 

 neurin, C^Hj^NIj, which has the same composition as the coiTe- 

 sponding derivative of cholin, would yield, on treatment with 

 silver oxid, the oxyethyl base. Baeyer was apparently not able to 

 effect this change, since he held that the vinyl base may be pre- 

 pared from the oxyethyl, but that the reverse, the preparation of 

 the oxyethyl base from the vinyl compound, could not be brought 

 about. This, however, has been successfully accomplished by 



