574 MR. youatt’s veterinary lectures. 
the division into lobes is lost; and we have one connected body 
with deep sulci running in various directions, but mostly trans¬ 
versely. The convolutions, less marked in the brain of the qua¬ 
druped than in that of the human subject, are far more promi¬ 
nent, and the sulci deeper in the cerebellum of our patients than 
in that of man. Instead of the fissures not being more than a few 
lines in depth, some of the lobuli maybe separated almost to the 
centre of the cerebellum. The division between the cineritious 
and medullary portions is more distinctly marked than in the 
cerebrum : the cineritious is here also the cortical or outer layer, 
lining either the external or internal surface of the lobuli; while 
the medullary substance occupies the central part. Here also, 
more evidently than in the cerebrum, the cortical is in detached 
portions, and the medullary connected together, and tending to¬ 
wards the centre through the whole of the cerebellum ; so that 
when we make a vertical incision through either of the lobes, we 
have a beautiful resemblance of a tree (the arbor vita), the trunk 
and the branches composed of medulla—the foliage consisting 
of cineritious matter. 
The Crura Cerebelli. —The trunk from each side of the cere¬ 
bellum takes a direction anteriorly and downwards, and reaches 
or rather forms the base of the tuber annulare or pons varolii. 
These trunks are the crura cerebelli, conveying or combining the 
influence or power of the cerebellum. These crura prolonged, 
and widening as they come more into sight, and meeting on the 
centre of the base of the brain, constitute the tuber or pons. 
The crura cerebelli are meeting each other transversely, and 
forming a kind of arch or bridge, and the crura cerebri are pass¬ 
ing under the arch. What admixture of substance or influence 
takes place, I will presently inquire; but, first of all, I must 
speak of the function of this little brain. 
Function of the Cerebrum and Cerebellum, —I have endea¬ 
voured to trace the connexion between the medullary and cine¬ 
ritious portions of the brain, and the prevalence of the animal 
or intellectual principle. My conclusions, advanced with some 
degree of hesitation, were founded on the seeming connexion be¬ 
tween the quantity of cineritious matter in the common sensorium, 
and the degree of intelligence which the animal possessed. In 
proportion as the medullary substance prevailed, the quadruped 
stood low on the scale of intelligence; and so far as we could as¬ 
certain it, proceeding upwards from the ox and the horse to the 
dog, in proportion as the cineritious matter increased, the reason¬ 
ing faculty was developed. Other arguments drawn from expe¬ 
riments on living animals I purposely reserved, until we were 
enabled to compare these two divisions of the brain together. 
