LECITHINS. 235 



stearyl-lecithin studied by HOPPE-SEYLER and DiACONOW, 1 which probably 

 has a different structure, has the formula C 4 4H 9 oNPO9. ERLANDSEN 

 gives the formula C 4 3H 8 oXPO 9 for the lecithin isolated by him from the 

 heart muscles. 



On saponification with alkalies or baryta-water, lecithin yields fatty 

 acids, glycerophosphoric acid, and choline. It is only slowly decomposed 

 by dilute acids. Besides small quantities of glycerophosphoric acid we 

 have large quantities of free phosphoric acid split off. The lecithins are 

 also decomposed by enzymes (lipase) with the splitting off of fatty 

 acids. 



Lecithin is optically active, and as the glycerophosphoric acid which 

 can be split off is also active, WILLSTATTER and LUDECKE 2 claim that the 

 phosphoric acid is not bound on the middle unsymmetric CH group, but 

 rather at the end CH 2 group of glycerin. 



Lecithin, according to HOPPE-SEYLER, S is found in nearly all animal 

 and vegetable cells thus far studied, and also in nearly all animal fluids. 

 It is especially abundant in the brain, nerves, fish eggs, yolk of the egg, 

 electrical organs of the Torpedo electricus, semen, and pus, and also in 

 the muscles and blood corpuscles, blood plasma, lymph, milk, especially 

 woman's milk, and bile. Lecithin is also found in different pathological 

 tissues or liquids. As the presence of lecithin is only indirectly deter- 

 mined by the detection of phosphorous in organic combinations, it must 

 be borne in mind that the above assertions relate chiefly to the occur- 

 rence of phosphatides. 



The same also applies to the claims as to the quantity of lecithin 

 in various organs and tissues as well as in different ages. In these cases 

 the lecithin has not been prepared in a pure state, and the determina- 

 tions represent only the approximate quantity of phosphatides. These 

 determinations of SIWERTZOW, GLIKIN and NERKING/* show that lecithins 

 (phosphatides) occur abundantly in the bone marrow, suprarenal capsule, 

 heart and lungs, besides in the spinal marrow, brain, and egg, and 

 also that the quantity varies strikingly in different varieties of ani- 

 mals. NERKING found 41.7 per cent lecithin in the bone marrow and 

 21.33 per cent in the suprarenal capsule of the urchin when calculated 

 on the living organs, while the corresponding results in the rabbit were 

 2.71 and 2.39 per cent, respectively. These determinations have also 

 shown that the amount of lecithin is especially higher in the new born, and 

 that the phosphatides to all appearances are of the greatest importance 



1 Hoppe-Seyler, Med. chem. Unters., Heft 2 and 3. 



2 Ber. d. d. chem. Gesellsch.. 37. 



3 Physiol. Chem. Berlin, 1877-81, p. 57. 



4 Siwertzow, see Biochem. Zeitschr., 2, p. 310; Glikin, Biochem. Zeitschr., 4 and 

 7; Nerking, ibid., 10. 



