57G BRAIN AND NERVES. 



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

 derived from a decomposition of phosphatides, which exist in the fatty 

 tissue between the nerve-axes, it is difficult to decide what part the fatty 

 acids and neutral fats play as constituents of the real nerve-substance. 



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

 double-contoured drops or fibres, not unlike double-contoured nerves, are formed. 

 These remarkable formations, which can also be seen in the medulla of the dead 

 nerve, have 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 impure protagon, lecithin, and impure choles- 

 terin, and they depend upon a decomposition of the constituents of the medulla. 



The extractive bodies seem to be almost the same as in the muscles. 

 One finds creatine, which may, however, be absent (BAUMSTARK), purine 

 bases, inosite, choline, paral-actic acid (MORIYA), phosphocarnic acid, uric 

 acid, and the diamine neuridine, C 5 Hi 4 N 2 , discovered by BRIEGER * 

 and which is most interesting because of its appearance in the putrefac- 

 tion of animal tissues or in cultures of the typhoid bacillus. Under 

 pathological conditions leucine and urea have been found in the brain. 

 Urea is also a physiological constituent of the brain of cartilaginous 

 fishes. 



Of the above-mentioned constituents of the nerve-substance pro- 

 tagon and the cerebrins or cerebrosides must be specially described. 



Protagon. Under this name LIEBREICH described a crystalline, 

 nitrogenous and phosphorized substance, which has been found in the 

 brain of man, mammalia and also birds (ARGIRIS) but not in the brain 

 of. fishes (ARGIRIS). Its elementary composition, according to GAMGEE 

 and BLANKENKORN is C 66.39, H 10.69, N 2.39 and P 1.07 per cent. The 

 results for carbon and phosphorus, namely 66.25 and 0.97 per cent, 

 found by KOSSEL and FREYTAG, correspond well with these figures while 

 the result for the nitrogen, 3.25 per cent, is too high. They also found, 

 as shown previously by RUPPEL, that protagon contains sulphur, namely 

 0.51 per cent. CRAMER also found that the protagon contained sulphur, 

 but obtained about the same figures as GAMGEE and BLANKENHORN. 

 Recently WILSON and CRAMER 2 have reported newer analyses and they 

 find for protagon, recrystallized 4-5 times, nearly the same figures as 

 GAMGEE and BLANKENHORN, namely C 66.53, H 10.97, P 0.95 and S 

 0.73 per cent. They consider protagon as a unit substance. 



1 Brieger, Ueber Ptomaine, Berlin, 1885 and 1886. 



2 Lieberich, Annal. d. Chem. u. Pharm., 134; Argiris, Zeitschr. f. physiol. Chem., 

 57; Gamgee and Blankenhorn, ibid., 3; Kossel and Freytag, ibid., 17; Ruppel, 

 Zeitschr. f. Biol., 31; Cramer, Journ. of Physiol., 31, with R. A. Wilson, Journ. of exp. 

 Physiol., 1, with Lockhead, Bioch. Journ., 2. 



