CHEMICAL BASIS OF THE ANIMAL IinPY. l:;r, 



In accordance with these views the constitution of lecithin may 

 be most adequately represented by the following formula : 



/j.(C ll H ta _ 1 O.)j 



\ .PO( OH 



N O.C S H 4 . (CH,),N.OH, 



where CaH^Oj represents the radicle of a fatty acid which in 

 ordinary lecithin appears to be that of stearic, viz. Ci 8 H 86 O . 



Glycerinphosphoric acid. C,H 9 P0 6 . [C 8 H 6 . (OH) 2 . 0. PO (OH ) ,]. 



Occurs as a product of the decomposition of lecithin, and hence 

 is frequently found in those tissues and fluids in which the latter 

 is present. It may occur occasionally in urine. 1 



The acid is dibasic and forms salts which are usually, so far as 

 they are known, soluble in cold water, but the lead salt is an ex- 

 ception to this rule and may hence be used as a precipitant. The 

 salts are insoluble in alcohol. 



It may be prepared by the decomposition of lecithin \\l\f\\ 

 boiled with caustic alkalis or baryta. It may also be synthetised 

 by the direct action of phosphoric anhydride or glacial phosphoric 

 acid on glycerin. The formation by this method may be regarded 

 as resulting from the union of one molecule of glycerin with one 

 of phosphoric acid and elimination of one molecule of water. 



Cholin. C 5 H 16 N0 2 . |(CH,) 8 = N^ c C H S (OH ) 1 tn 

 ethyl-ammonium hydroxide. 



Discovered by Strecker a among the products of the decomposi- 

 tion of pigs'-bile and subsequently of ox-bile, whence tin- nuim- 

 cholin. It does not occur in the free state except as a product of 

 the decomposition of lecithin, but has been mvntly obtained in 

 extracts of the suprarenals. 3 It is a colourless fluid, of oily con- 

 sistence, possesses a strong alkaline react inn. and t'nriii^ \\ith acids 

 very deliquescent salts. The salts with hydrochloric acid and 

 with the chlorides of platinum and of gold are tin- most important. 



Cholin is a most unstable body, mere heating of its aqueous 

 solution sufficing to split it up into glycol. trimethvlamin and 

 ethylene oxide. 



Since it is a product of the decomposition of lecithin it is best 



1 Sutnitsdiowsky, '/.(. f. phi/iiol. Chem. Bd. iv. (1880), S. 214. But see also 

 Robii; Pkarm, T. n \> :>TJ. ami Chrw. C.nt,,,!!.. is8, S. 186. 



a .Inri. d. Chfm. n. I'luirm. 15,1. .\\iil. (l6a). S. 3.VJ ; H.I. cxi.vin. (1868), S. 76. 

 Marino-Zuco, Rend. d. /?. accad. d. Lincei, 1888, p. 835. 



