DR. D. FERRIER ON THE BRAIN OF MONKEYS. 
467 
optic tract was adherent to the hippocampal convolution. The dura mater in the left 
sphenoidal fossa, and on the left petrous bone, and on the basilar process had a yellowish 
Fig. 22. 
Fig. 22 represents the lesion of the uncinate gyrus 
and the direction of the sinus caused by the cautery 
in Exp. XYII. 
Fig. 23. 
Fig. 23 represents the outer surface of the same 
hemisphere, and the dotted lines indicate the track 
of the cautery in Exp. XYII. The black dot at the 
extremity of the upper temp.-sph. fissure indicates the 
point at which the track terminated externally. 
aspect. The inflammation appeared to have spread from the point in the left sphenoidal 
fossa where the cautery had emerged from the brain. The optic thalamus and other 
ganglia were normal, except perhaps slight extension of the inflammation up the left 
optic tract to the left nates and testes. 
This experiment became complicated by the results of basilar inflammation, but it is 
possible to trace the course of the phenomena. 
The cautery, as determined by the points of entrance and exit, seems, after ploughing 
along the upper end of the uncinate gyrus, just to have missed the hippocampus and 
descending pillar of the fornix. At first the effects were negative or nearly so ; but 
gradually the animal began to exhibit failing sensation, as indicated by the diminution 
of reaction to tactile impressions and inability to use the right hand, until ultimately 
sensation became to all appearance abolished, or nearly so, on the right side. This would 
coincide with the advance of softening into the hippocampus, as w r as found to be the case 
after death. 
Whether the spasmodic affection of the right side is to be attributed to sensory 
irritation excited by the progress of inflammatory softening is a question ; but it had 
also a possible origin in the basilar inflammation which, extending from the left sphe- 
noidal fossa, naturally would affect the left half of the pons and medulla first, and show 
its effect by convulsive action of the opposite side of the body in the first instance. 
This complication renders it difficult to estimate the exact effect of the lesion in the 
temporo-sphenoidal lobe ; but the difference observed in the reaction of the two sides to 
the hot iron strongly confirms the view that this was dependent on the lesion of the 
hippocampus in the left hemisphere. 
The following experiment serves to confirm this view. 
3 q 2 
