240 ANIMAL FATS AND PHOSPHATIDES. 



be remarked that MODRAKOWSKI l claims that the above action of choline 

 does not exist in pure choline, but is due to a .contamination with very 

 small amounts of another substance having powerful action. Choline 

 decomposes very readily and hence becomes easily contaminated. The 

 choline isolated from tissues is readily contaminated, hence the claims 

 made as to the physiological importance of choline in secretion require 

 further confirmation. 



Choline is a syrupy fluid, readily misciblewith absolute alcohol. Hydro- 

 chloric acid gives with it a compound which is very soluble in water and 

 alcohol, but insoluble in ether, chloroform, and benzene. This compound 

 forms a double combination with platinum chloride, is soluble in water, 

 insoluble in absolute alcohol and ether, and crystallizing ordinarily in six- 

 sided orange-colored plates. This compound is used in the detection 

 and identification of this base. Choline also forms a crystalline double 

 compound with mercuric chloride and with gold chloride. Choline 

 is precipitated by potassium iodide and iodine (GULEWITSCH), and potas- 

 sium triiodide can be used for the quantitative estimation of this base 

 (STANEK 2 ). On heating the free base it decomposes into trimethyl- 

 amine, ethylene oxide, and water. 



In preparing choline from lecithins, and also for the detection of 

 lecithin in an alcohol-ether extract, proceed as follows: The residue from 

 the above or the solid lecithin is boiled one hour with baryta -water, 

 filtered, and the excess of baryta precipitated by C0 2 ; filter while hot, 

 concentrate to a syrup, and extract with absolute alcohol, when the 

 insoluble barium glycerophosphate remains ; then precipitate the filtrate 

 with an alcoholic platinum chloride solution. 



CH 2 .OH 



Glycerophosphoric acid, C 3 H 9 PO 6 = CH.OH , is a bibasic acid which prob- 



CH 2 O\ 



OH-)PO 



OH/ 



ably occurs in the animal fluids and tissues only as a cleavage product of lecithins. 

 According to WILLSTATTER and LUDECKE 3 the glycerophosphoric acid split off 

 from lecithins is optically active. Its barium and potassium salts are levorota- 

 tory, and behave in certain regards differently from the corresponding salts of 

 synthetically prepared glycerophosphoric acid. 



The diaminomonophosphatides have unfortunately been little studied, 

 and the triamidomonophosphatide neottin will be discussed in a sub- 



1 Pfl user's Arch., 124. 



2 Gulewitsch, Zeitschr. f. physiol. Chem., 24; Stanek. ibid., 56. In regard to the 

 quantitative estimation see also Kiesel, ibid., 53; Stanek, ibid., 54; Moruzzi, ibid., 

 55, and MacLean, ibid., 55. 



3 Ber. d. d. chem. Gesellsch., 37. 



