OCCURRENCE OF LECITHINS 43 



FURTHER REFERENCES. 



Ivanow : " Beih. Bot. Cent.," 1912, 28, 159. 



Lewkowitsch : " Chemical Technology and Analysis of Oils, Fats and 

 Waxes," London, 1909. 



PHOSPHATIDES, LECITHINS, OR PHOSPHOLIPINS. 



Closely related to the fats is the group of substances known 

 as phosphatides, phospholipins or lecithins, the last name being 

 derived from the Greek Xe/ct^o?, meaning egg yolk, from which 

 substance the first representative of the class was prepared. 



The name phosphatide was first given by Thudichum to 

 a number of substances containing phosphorus which he 

 obtained from brain. Subsequently Overton introduced the 

 term lipoid to represent a group of substances occurring in 

 the animal tissues which resembled fats in their solubilities. 

 Leathes uses the term phospholipins, in place of phosphatides, 

 to denote compounds of fatty acids containing phosphorus and 

 nitrogen, and proposes the name of lipins for compounds of 

 fatty acids that contain nitrogen but no phosphorus. 



OCCURRENCE. 



Lecithin compounds occur in the grains of cereals, in the 

 seeds of several Leguminosai, Ricinus, and species of Pinus ; 

 in the leaves of Castanea, and in Fungi ; they are also widely 

 distributed in animals. In fact, these substances are stated to 

 occur in small quantities in all living cells, and they appear to 

 be more especially abundant where fats occur. 



The approximate amount of lecithin contained in various 

 substances may be seen from the following table : — 



Egg yolk 9 "4 per cent 



Liver 2-r ,, 



Blood 1-8 „ 



Leguminous seeds .... o*8-i"64 per cent 



Cereals o-25-o-53 ,, 



Botanically, the term lecithin is generic, and plant products so 

 called have not yet been obtained in a pure state and contain 

 other substances of a similar nature. 



PREPARATION. 

 The most convenient source for the preparation of lecithin 



