Physiology. — “The Quantitative Relations of the Nervous System 
Determined by the Mechanism of the Neurone.” By Prof. 
Eve. Durois. 
(Communicated at the*meeting of December 27, 1919). 
For animal species with the same organisation of the nervous 
system (homoneurie species) the quantity of the neurone varies in 
the same way, relative to the body quantity, as that of the brain’), 
ie. proportional to P°5 or Pb. The establishment of this fact may 
certainly be considered as a confirmation of the validity of our 
present views of the constitution of the nervous system, which, on 
solid grounds, was considered, also in its highest forms, as entirely 
consisting of series of structural elements, highly specialized cells, 
the neurones, which conduct processes of stimulation (impulsions) in 
definite directions, and preserve conditions of stimulation (impressions), 
directly or indirectly dependent on the sense organs and the muscles, 
and which are, accordingly, in mechanic dependence on the body. The 
other constituent parts of the nervous system were thought to be 
non-essential: they were supposed to serve only as a support and 
protection to the neurones. 
From the parallelism of the relation of the total quantity of the 
brain with that of the neurone, including the medullary sheath and 
the neurilemma, it also appears that the same significance must be 
!) We refer here to a ratio of two quantities expressed in the same unit with 
regard to a ratio of two other quantities which may be expressed in another unit, 
provided it be the same for these latter two. For two animal species whose body 
weights and brain weights are P and P,, and W and W, and whose volumes of 
homologous neurones and their ganglion cells are N and Nj, C and (Cj, the 
following equations may be pul: 
(= z C 4 EAN NEN i LENG 
: 5) — C: an P, — N, as we as P, — 
Actually it appeared that: 
; (ON 
D000: Ol) ter cand (5 ) = 
a 
The specific weight of the components of the nervous system (about equal to 
E 
= . 
EH, 
N 
1 
that of the body) lies, indeed, so little above 1 that, when the ratio of the volumes 
is taken, instead of that of the weights of these components to the body weight, 
the exponents are only reduced to 0.2754 and 0.5508 (instead of 0.27 and 0.55). 
44 
Proceedings Royal Acad, Amsterdam. Vol. XXII. 
