240 BACTEKIAL POISONS. 



and evaporated. The lecithin thus obtained is almost per- 

 fectly pure, but contains traces of cholesterine. To com- 

 pletely purify it, it can be dissolved in as little absolute 

 alcohol as possible, and set aside to reprecipitate in the 

 cold, —5 to 15°. 



In regard to the genesis of choline the preponderance of 

 testimony goes to show that it is derived from the decom- 

 position of lecithin, which, according to the researches of 

 DiAKONOW and others, is one of the most widely distributed 

 compounds, occurring in greater or less quantity in all of 

 the animal tissues. Lecithin, which is a complex esther 

 (Strecker, Hundbshagen, Gilson), decomposes under 

 the action of acids and alkalies into a base (choline) 

 glycerin, phosphoric acid, and fatty acids (stearic, oleic, 

 palmitic, etc.). Gilson has shown that dilute sulphuric 

 acid slowly decomposes lecithin, forming choline, which, 

 after a few days, disappears ; on the other hand, sodium 

 hydrate, in even 1 per cent, solution, rapidly decomposes 

 it. This change is undoubtedly accomplished in a similar 

 manner through tlie agency of bacteria. Brieger (II., 

 17) is inclined to believe that choline exists preformed in 

 the various tissues, inasmuch as he has been unable to ob- 

 tain it from the brain, which is rich in lecithin, by boiling 

 with 2 per cent, hydrochloric acid. (See Schulzb, page 

 242.) Prolonged heating with concentrated hydrochloric 

 acid was necessary in order to obtain any choline from the 

 brain. This result of Brieger's is somewhat at variance 

 with that of Marino-Zuco (see Selazione, etc., pages 29, 

 30, and -38), who obtained from 25 grammes of lecithin, by 

 the method of Stas, a small quantity of the aurochloride 

 of a base, while from a similar amount he obtained more 

 relevant quantities by the method of Dragendorff. 



The occurrence of choline in the vegetable kingdom 

 would be inexplicable to us at present were it not that 

 we now know of the existence of lecithin-like bodies in 

 plants, from the decomposition of which substantially the 

 same products are obtained as from the lecithin obtained 

 from the animal tissues. The existence of such a body in 

 plants was first predicted by Scheibler in 1870, who was 



