464 MR. YOUATt’s veterinary LECTURES. 
human being, how broad, and rounded, and bulky, compared 
- with the elongated flat one of the horse and the ox. The 
human brain is double the size of that of the horse, and, com¬ 
pared with the bulk of the animal, it is many times the size. 
Comparative anatomists have given us a kind of table of the 
proportionate weight of the brain. In the human being it has 
been calculated at g 3 ^th part of the weight of the frame; in the 
dog, according to his size, it varies from ^^^th to -g-^xjth part; in 
the horse it is 4 'j 7 yth; in the swine y^^th; in the sheep ■y;|^^th 
(Cams strangely says ^th) j and in the ox -^^^jth. Do we trace 
any connexion between this relative bulk of brain and the quan¬ 
tum of mind? We seem to have been classing our patients 
pretty nearly in proportion to their degree of intelligence. But 
we are not yet prepared for this. 
Form of the Brain .—The flatness of the brain of quadrupeds, 
compared with the rotundity of the human brain, is one of the 
first things that will naturally attract our attention; and the 
flatness, when we turn the brain over, is far more remarkable 
below than above. The convexity of the middle lobes is strangely 
diminished, while the posterior lobe is in a manner lost. These 
circumstances, and particularly the last of them, account for the 
great difference in the base of the cranium in the human being 
and the quadruped,—the deep concavities of the one, and the 
comparative flatness and regularity of the other. Observe the 
prolonged oval shape of the brain in the horse, the ox, and sheep; 
somewhat broader, indeed, posteriorly than anteriorly, and this 
assuming almost the form of a triangle in the dog. 
Irregularities of Surface .—We recognize an irregularity of 
surface, as on the human brain—certain prominences and de¬ 
pressions, but not so marked. The surface of the brain in the 
quadruped is comparatively tame and inexpressive; nay, some 
of our occasional patients have no convolutions on the surface 
of the brain; they are not found in the hare, the rabbit, the 
rodentia generally, or the bird. They are not so bold or so deep 
in the ox as in the horse, nor so much so, compared with 
the difference of bulk, in the horse as in the dog,—the swine 
holding an intermediate place between the two. We must not 
dare to connect this with the proportion of animal food by which 
each is nourished, although, in proportion as he is carnivorous, 
his brain is usually convoluted ; but I am afraid that we do not 
know enough of the functions of any part of the brain of the 
quadruped to associate these convolutions with anything else. 
Some comparative anatomists, whose descriptions are generally 
distinguished for their accuracy, have told us, that ‘Mn the 
opposite hemispheres of the cerebrum in animals, the most exact 
