668 
Jackal is three times that found between the Jackal and the Fennec. 
Likewise in Rodentia, the calculation of 2 between the large Malayan 
Squirrel and the Common Squirrel gives double the value obtained 
by comparison of this European species with the small Hudson 
Squirrel; between the Brown and the Black Rat z is found more 
than three times as much as between the Black Rat and the House 
Mouse '). 
Nor can such a quantity, which would only serve for psychical 
functions and be independent of the mechanism of the body, be 
reasonally .assumed to exist in the human brain. The hypothesis 
under consideration, which lacks anatomical or physiological foun- 
dation, must, therefore, be relinquished. 
This can be stringently proved from the mechanism of the neurone. 
If there is no room for a non-mechanically determined quantity in 
the neurone, then this cannot either be the case in the complex of 
neurones, the nervous system. 
The existence of fixed quantitative relations between the neurone 
and the body, and between the parts of the neurone inter se left 
hardly any room for doubt that these relations are determined 
mechanically; a closer consideration of them gives complete certainty 
on this head. 
1) Let i be the hypothetical brain quantity (the weight), set apart for the 
“intellect”, m a constant for the influence of the “masse organique” (Manouvrrer) 
on the quantity (weight) of the brain, -P and P, the body weights of two com- 
pared species, one of which is greater than the other, E and & their brain 
weigths, then on the supposition, 
H=mP +7 and L, =>mP, +1 
from which 
BD. 
ATS 
P—P, 
P(E—E)) 
and 1= PP, . 
In grams the weights of P and E are, for Canis lupus 37000 and 189, for 
Canis aureus 10000 and 73 (these two according to L. Lapicgue in Bulletin du 
Muséum d’histoire naturelle. Paris 1912. N°. 1, p. 4), for Canis zerda 1500 and 
25 (according to B. Krarr, in Sitzungsberichte der Gesellschaft naturforschender 
Freunde, Berlin 1918, p. 37), for Sciurus bicolor, Sciurus vulgaris, and Sciurus 
hudsonicus 1400 and 12, 323 and 6.1, 159 and 4.1, for Mus norvegicus, Mus rattus 
and Mus musculus 448 and 2.36, 200 and 1.59, 21 and 0.43 (according to my 
records in Zeitschrift fiir Morphologie und Anthropologie, 1914, p. 327, and my 
Paper in the Verhandelingen of this Academy of 1897), for Felis leo, Felis concolor 
and Felis domestica 119500 and 219, 44000 and 137.5, 3300 and 31 (according 
to records in the same Paper). a 
