614 BRAIN AND NERVES. 



According to FR. FALK l the cerebrosides occur in the medullary 

 nerve fibers as well as in the nerves without medullas. These latter 

 yielded much less substance on extraction than the medullary, namely, 

 11.51 per cent extract as compared to 46.59 per cent. The extract of 

 the first was poorer in cerebrosides, but richer in cholesterin, cephalin 

 and lecithin, as shown by the following figures. 



Non-medullary fibers Medullary fibers in 



in p. m. of the total p. m. of the total 



extract extract 



Cholesterm 470 250 



Cephalin 237 124 



Cerebrosides 60 182 



Lecithins 98 29 



S. FRANKEL and L. DIMITZ 2 find that the spinal marrow contains on 

 an average 740 p. m. water, 180 p. m. lipoids and 80 p. m. protein. The 

 quantity of cholesterin (in the fresh, spinal marrow containing water) 

 is 40 p. m., the unsaturated phosphatide 120 p. m., and the saturated 

 15 p. m. The spinal marrow is the richest part of the nervous system 

 in unsaturated phosphatides and it contains abundance of cephalin. 



According to NOLL the white substance of the spinal marrow^ is some- 

 what richer in protagon than the brain, and in nerve degeneration the 

 quantity of protagon diminishes. The method used by him would not 

 allow of an exact determination of the disputed substance protagon. 

 MOTT and HALLIBURTON 3 have also shown that in degenerative diseases 

 of the nervous system, the quantity of substances containing phosphorus 

 diminishes, and that in these cases, especially in general paralysis, choline 

 passes into the cerebrospinal fluid and the blood. In degenerated nerves, 

 the quantity of water increases, and the phosphorus decreases. On 

 comparative investigations of the central nervous system of normal 

 persons, and those afflicted with dementia pracox (5 cases), Kocn 4 found 

 that the variation from the normal composition was not great enough 

 nor so constant that positive conclusions could be drawn therefrom. 



The quantity of neurokeratin in the nerves and the different parts 

 of the brain has been carefully determined by KUHNE and CniTTENDEN. 5 

 They found 3.16 p. m. in the plexus brachialis, 3.12 p. m. in the cortex 

 of the cerebellum, 22.434 p. m. in the white substance of the cerebrum, 

 25.72-29.02 p. m. in the white substance of the corpus callosum, and 

 3.27 p. m. in the gray substance of the cortex of the cerebrum (when 



1 Bioch. Zeitschr., 13. 

 Ibid., 28. 



8 Noll, Zeitschr. f. physiol. Chem., 27; Mott and Halliburton, Philos. Transactions, 

 Ser. B., 191 (1899), and 194 (1901). 

 * Arch, of Neurology, 3. 

 6 Zeitschr. f . Biologic, 26. 



