18 
TUMOUR IN THE LATERAL VENTRICLE. 
hemispheres of both cerebral lobes are removed, the animal 
is thrown into a state of profound sleep and unconscious¬ 
ness ; having no sense of what is passing. When the lobes 
of the cerebellum are removed, and those of the cerebrum 
are uninjured, the animal possesses its senses and the full 
power of its will, but appears as if intoxicated, and totters 
and staggers with great irregularity. The want of feeling in 
a large portion of the brain, when cut or pricked, is remark¬ 
able. The membranes, cerebral hemispheres, corpus cal¬ 
losum, anterior and posterior commissures, are without 
feeling. Also all the upper part of the cerebellum is without 
feeling: it is only manifest on appi'oaching its crurae. If 
the corpora striata are pierced into the medullary substance, 
signs of feeling are manifested. In the tlialami it is more so; 
but the tubercula quadrigemina, when pierced, produce great 
disturbance, trembling, agitation, and convulsions: and, if it 
be the medulla oblongata, or pons varolii, that is injured, the 
effects are more violent. Such are some of the results of 
vivisection; but for which experiments we must have been 
wholly ignorant of at the present day, as dissection of dead 
bodies could never have revealed these phenomena. Vivi¬ 
section has made known to us the co-operation of the fifth 
pair with the special nerves of the senses of smell, sight, 
hearing, and taste ; which were not previously known to 
have any relationship between them. It has revealed to us 
that the superior columns of the spinal cord are the strands 
from which the sensory roots of the spinal nerves proceed, 
and the inferior to be those from which the motor are 
derived; and we now know what parts of the brain are 
endowed with sensibility and what do not possess it. Surely 
these are highly important facts that we have arrived at 
through experiments upon living animals, and such that no 
other could have determined. We must remember, however, 
that they are the effects of lesions of the brain in healthy 
animals, in which this organ is also healthy; and how far 
this information will avail us in diseases of it, is for future 
consideration. 
Let us now examine some of the phenomena produced by 
morbid lesions of the brain. We have no means of ob¬ 
serving, or but very imperfectly, the early symptoms of 
inflammation of the membranes, or of the substance of the 
brain, or of both: the cephalalgia and incoherency of 
speech, so important in guiding the diagnosis of the phy¬ 
sician, cannot be rendered available in the examinations of 
animals by the veterinary surgeon. 
The symptoms of inflammation of the membranes, and of 
