274 PHYSIOLOGICAL CHEMISTRY. 



yields easily, as decomposition products, lecithin, fatty acids, and a 

 nitrogenized substance, cerebrin; this last probably does not occur 

 preformed in the brain, but is more likely a product of transforma- 

 tion (BAUMSTABK). That lecithin also is pre-existent in the brain 

 and nerves can hardly be doubted. The investigations thus far 

 made have not shown decidedly whether ifc is more abundant in the 

 gray or white substance. Fatty acids and neutral fats may be 

 prepared from the brain and nerves; but as these may be readily 

 derived from a decomposition of lecithin and protagon, which exist 

 in the fatty tissue between the nerve-tubes, it is difficult to decide 

 what part the fatty acids and neutral fats play as constituents of 

 the real nerve-substance. Cholesterin is also found in the brain and 

 nerves, a part free and a part in chemical combination of which we 

 know nothing about (BAUMSTARK). Cholesterin seems to occur in 

 greater abundance in the white substance. Besides these substances 

 the nerve tissue, especially the white substance, contains doubtless 

 a number of other constituents not well known, and among which 

 are several containing phosphorus. THUDICHUM asserted that he 

 had isolated a number of phosphorized substances from the brain 

 which he divided into three principal groups: kepalines, myelines, 

 and lecithines. But thus far this assertion has not been confirmed 

 by other investigators. 



By allowing water to act on the contents of the medulla, round, 

 or long double-contoured drops or fibres, not unlike double-con- 

 toured nerves, are formed. This remarkable formation, which can 

 also be seen in the medulla of the dead nerve, has been called 

 " myeline forms" and they were formerly considered as produced 

 from a special body, " myeline." Myeline forms may, however, be 

 obtained from other bodies, such as protagon, lecithin, .fat, and im- 

 pure cholesterin, and they depend on a decomposition of the con- 

 stituents of the medulla, chiefly the protagon. 



The extractive bodies seem to be almost the same as in the mus- 

 cles. We find : creatin, which may, however, be absent (BAUM- 

 STARK), xanthin bodies, inosit, lactic acid (also fermentation lactic 

 acid), uric acid, jecorin (according to BALDI, in the human brain), 

 and neuridin, discovered by BRIEGER and which is most interest- 

 ing because of its appearance in the putrefaction of animal tissues. 

 Under pathological conditions leucin and urea have been found in 



