r ROTE IDS OF NERVOUS TISSUES. 
117 
marised in the following table of mean analyses. The organs wore from 
adull human beings, dogs, cats, and monkeys: — 
Wat it. 
Solids, 
Percentage 
"t Proteids 
in Solids. 
Grey matter of -carebrum . 
83-467 
16-533 
51 
White „ „ 
69-912 
30-088 
33 
Cerebellum .... 
79-809 
20-191 
42 
Spinal cad as a whole 
71-641 
28-359 
31 
Cervical cord .... 
72-529 
27-471 
31 
Dorsal cord .... 
69-7-".: 
30-245 
28 
Lumbar cord .... 
72*639 
27-631 
33 
Sciatic nerves .... 
61-316 
38-684 
29 
This table illustrates the fact that the amount of grey matter, of 
water, and the percentage of proteid in the solids, vary directly the one 
with the other. This is very well seen in the different regions of the 
spinal cord. The percentage of proteid in the white matter of the 
brain is a little higher than in the spinal cord ; this exception is 
perhaps to be explained by the high percentage of neurokeratin : in 
white matter, which, according to the methods used, would be included 
with the proteids. 
Reaction of nervous tissues. — Heidenhain 2 and Gscheidlen 3 state that 
the normal reaction of the axis cylinder is alkaline ; on death or on 
long-continued activity the reaction becomes acid. They further state 
that the grey matter is acid even during life. O. Langendorff 4 found 
the reaction of the central nervous system alkaline during life ; the 
alkalinity rapidly diminishes after death, or on stoppage of the circula- 
tion. S. Moleschott and Battistini 5 found both central and peripheral 
portions of the nervous system acid, especially the grey matter; this was 
increased by activity. 
In my own work I found in animals that the fresh tissues were 
invariably alkaline, but they became rapidly acid, especially the grey 
matter. In the human brains I received from the post-mortem room the 
reaction of the grey matter was always, of the white matter often, acid. 
This I put down to changes after death, for at least twenty-four hours 
had always elapsed since death. 
The acidity is due to lactic acid : but, according to M tiller and 
Gscheidlen, it is not sarcolactic acid but the fermentation lactic acid 
(optically inactive ethylidene-lactic acid). Midler also obtained traces 
of formic acid. 
Proteids of nervous tissues. — The large quantity of these, especi- 
1 The percentage of neurokeratin is in grey matter, 0'3 ; in white matter, 2 "2 to 2 -9 ; and 
in nerve, - 3 to 0"6 (Kuhne and Chittenden, Ztsehr.f. Bio!., Miinchen, Bd. xxvi. S. 291). 
2 Cmtralbl.f. d. m>.d. U'issrusr],.. Berlin, 1868, S. 833. 
3 Arch. f. d. ges. Physiol.. Bonn, Bd. viii. S. 171. 
4 Neurol. CerUralbl., Leipzig, 1885, No. 14; Centralbl. f. d. mcd. Wissensch., Berlin, 
1886, No. 25. 
5 Arch. Hal. de biol., Turin, vol. viii. p. 90 ; Chem. Cenlr.-BL, Leipzig, 1887, S. 1224. 
