BRAIN AND NERVE SUBSTANCES. 335 



BRAIN AND NERVE SUBSTANCES. CEREBRO- 

 SPINAL LIQUID. 



These tissues contain several peculiar compounds of which 

 our knowledge is limited, largely because of the great difficulty 

 in separation. The solid matter of the brain contains globu- 

 lins, nucleo proteids, cholesterol, lecithin, fatty bodies and 

 complex compounds not found elsewhere. Various soluble 

 extractives, somewhat similar to those from muscular tissue, 

 are also present. 



Protagon. This is an important constituent of the white 

 substance of the brain, which has this elementary composi- 

 tion, according to Gamgee : C 66.4, H 1.07, N 2.4, P 1.07. 

 But as other writers report rather widely different figures it 

 is likely that the pure substance has not yet been isolated. As 

 extracted by means of 85 per cent alcohol at 45 from the 

 minced brain, and purified by crystallization and washing with 

 ether, it is obtained as a white powder practically insoluble in 

 cold ether or alcohol and not properly soluble in water. With 

 much water it finally yields a gelatinous liquid, which suffers 

 decomposition readily. 



When warmed with dilute alkalies several cleavage prod- 

 ucts are obtained to which the names cerebrin, kerasin, cerc- 

 bron and encephalin have been given. These bodies are free 

 from phosphorus. On further cleavage with dilute acid they 

 yield a reducing sugar, probably galactose. No satisfactory 

 analyses of these products have as yet been obtained. It is 

 possible that they exist as glucosides. 



In the white substance of the spinal marrow protagon is 

 abundant. In degeneration changes in the tissues of the ner- 

 vous system it is probably this compound which suffers the 

 greatest alteration, with the production of neurine or choline 

 with marked toxic properties. It is likely that the neurine 

 comes from a lecithin body as one of the groups in the prota- 

 gon complex. 



Cerebro-spinal Liquid. This is a thin, watery liquid of 



