president’s address. 
7 
onward there was a gradual increase in the development of the 
brain, which soon dwarfed and overgrew the primary 
olfactory and optic ganglia which act as “ brain ” in the 
Invertebrates, also that as we reached the higher mammals 
the brain grew in size too quickly for its box, the skull, and 
had also for other reasons to extend its active area, the 
“ grey matter,” on its outer surface by foldings which are 
termed convolutions, and that in animals of the same order 
and of about the same size the number and complexity of the 
convolutions were indicative of the intelligence and mental 
capacity of the animal. Instances of this fact were given 
among aquatic mammals, in Seals, and in the Elephant among 
land mammals. The cerebellum, or little brain, was also 
described, its remarkable development in birds showing it to 
be, as well as for other reasons, the great controller and 
co-ordinator of action or movement. Unfortunately the 
lateness of the hour prevented Dr. Thomson from alluding, 
except in the most curtailed way, to the brain of the man-like 
Apes and of Man himself. He pointed out, however, the 
features common to the nervous system in the “ Primates,” 
how they were far in advance of other mammals, how some 
parts had disappeared and how others had made their 
appearance in the course of evolution, and finally showed the 
differences that distinguished the brain in man from that of 
the Chimpanzee, the Orang, and Gorilla, which approach man 
most closely in structure ; in size alone the difference being 
very great. Although an anthropoid Ape may weigh twice 
as much as a man, his brain weighs only about half that of 
a man’s. Explanations of this four-fold increase may be looked 
for in the mechanisms necessary for storing, correlating, and 
associating all that man has acquired by the “ gift ” or 
“ accident ” of articulate speech and all that language 
connotes. 
