80 
quently the longer the period of growth of the rest 
of the body, and the greater the bulk acquired, the 
greater the disproportion between the general bulk 
and that of the brain. In man it is about 1 to 25 
or 30: in simia capucina 1 to 25: in simia lar, 
lower in the scale, 1 to 48. In a rat the weight of 
the brain to that of the body was as 1 to 80: in a 
cat 1 to 40: in a sheep 1 to 35: in an elephant 1 
to 500. In quadrupeds the bulk of the cerebellum 
is greater in proportion to the rest of the brain than 
in man; where the hemispheres are so much de- 
veloped that the cerebellum forms but one ninth of 
the brain. In the mouse it is one half, in the beaver 
one third, in the horse one seventh. 
The body of a pigeon without feathers weighed 
against its brain was found to be nearly as 1 to 95, 
37 grains to 3360. The brain of an eagle is to the 
weight of the body as 1 to 160: in a siskin as 1 to 
230. The proportion of the spinal marrow to the 
brain is generally greater in birds than in mam- 
malia: in a pigeon the spinal marrow weighed 11 
grains, the brain 37, together 48: about 1 to 3. 
This proportion is nearly the same, however, in the 
rat. 
“ In amphibia®, the two divisions of the great 
central nervous mass are nearly similar: for although 
the brain is somewhat more developed than in fishes, 
the spinal marrow preponderates considerably in 
point of size. A tolerably large salamander weighed 
@ Carus, §. 307. p. 247. 
