COMPOSITION OF THE BRAIN. 581 



chloroform (see page 577), and purifying the separated cerebron from 

 contaminating phosphatides by precipitating these with an ammoniacal 

 solution of zinc hydroxide in methyl alcohol and recrystallizing the cere- 

 bron from methyl alcohol containing chloroform. 



The two monamido-monophosphatides, lecithin and cephalin, have 

 already been discussed in Chapter V. 



BETHE l prepared the following decomposition products from the brain 

 of the horse after treatment with CuCl 2 and alkali: Aminocerebrinic-acid glucoside, 

 C 44 H 81 8 N, which on boiling with hydrochloric acid yields cerebrinic acid, amino- 

 cerebrinic-acid chloride, and a hexose (galactose ?) ; phrenin, perhaps identical 

 with THUDICHUM'S krinosin; cerebrinic-phosphoric acid, and a stearic acid, differ- 

 ing somewhat from the ordinary one. 



Neuridine, C 5 Hi 4 N 2 , is a non-poisonous diamine discovered by BRIEGER, and 

 obtained by him in the putrefaction of meat and gelatin, and from cultures of 

 the typhoid bacillus. It also occurs under physiological conditions in the brain, 

 and as traces in the yolk of the egg. 



Neuridine dissolves in water and yields on boiling with alkalies a mixture 

 of dimethylamine and trimethylamine. It dissolves with difficulty in amyl 

 alcohol. It is insoluble in ether or absolute alcohol. In the free state, neuridine 

 has a peculiar odor, suggesting semen. With hydrochloric acid it gives a compound 

 crystallizing in long needles. With platinic chloride or gold chloride it gives 

 crystallizable double compounds which are valuable in its preparation and detec- 

 tion. 



The so-called CORPUSCULA AMYLACEA, which occur on the upper surface of the 

 brain and in the pituitary gland, are colored more or less pure violet by iodine 

 and more blue by sulphuric acid and iodine. They perhaps consist of the same 

 substance as certain prostatic calculi, but they have not been closely investigated. 



Quantitative Composition of the Brain. The quantity of water is 

 greater in the gray than in the white substance, and greater in new-born 

 or young individuals than in adults. The brain of the foetus contains 

 79_926 p. m. water. The observations of WEISBACH 2 show that the 

 quantity of water in the several parts of the brain (and in the medulla) 

 varies at different ages. The following figures are in 1000 parts A for 

 men and B for women : 



20-30 years. 30-50 years. 50-70 years. 70-94 Years. 



Medulla oblongata 744.3 740.7 732.5 729.8 722.4 730.6 736.2 733.7 



Quantitative analyses of human brains at different ages, namely 

 6 weeks, 2 and 19 years, have been made by KOCH and MANN. 2 These 

 analyses show that with increasing age the water, proteins, extractives 

 and salts diminish relatively, while the phosphatides, cerebrosides and 

 especially cholesterin strikingly increase. The sulphur of the lipoids is 



1 Arch, f . exp. Path. u. Pharm., 48. 



2 Cited from K. B. Hoffmann's Lehrbuch d. Zooch., Wien, 1877, p. 121. 



3 Journ. of Physiol., 36, Proc. physiol. Soc., 1907. 



