87 
injury amid the general destruction caused by the lesions de- 
scribed. I cannot dismiss this hypothesis without calling atten- 
tion to the confirmation that would be given to Mr. Darwin’s 
views if M. Broca’s theory were correct, and this particular 
fold could be shown to be the seat of speech in man. And here 
I must call attention to the comparison which Carl Yogt makes 
between our quadrumanous cousins and ourselves. According 
to this distinguished naturalist, the apes have an extremely 
imperfect development of the third frontal convolution, and the 
same condition exists in the microcephali ; therefore, he says, as 
neither apes nor microcephali can speak. Comparative Anatomy 
gives a subsidiary support to the theory which places speech in 
this convolution. 
I have been in communication with Professor Yogt in refer- 
ence to this subject, and he has kindly favoured me with his 
views, which I consider so extremely pertinent to our subject, 
that I shall give them in his own words, as contained in an 
autograph letter to myself. 
The brain of man and that of apes, especially of the anthropoid apes 
(orang, chimpanzee, gorilla), are constructed absolutely upon the same type — 
a type by itself, and which is characterized, amongst other things, by the 
fissure of Sylvius, and by the manner in which the island of Beil is formed 
and covered ; thus in man, the third frontal convolution is extraordinarily 
developed, and covers partly the insula, whilst the transverse central convo- 
lutions are of much less importance. In the ape, on the other hand, the 
third frontal convolution is but slightly developed, whilst the central trans- 
verse convolutions are very large. 
To show the bearing all this has upon the seat of speech, I would refer 
to the microcephali, who do not speak ; they learn to repeat certain words 
like parrots, but they have no articulate language. Now, the microcephali 
have the same conformation of the third frontal convolution as apes ; they 
are apes as far as the anterior portion of their brain is concerned. Thus, 
man speaks ; apes and microcephali do not speak. Certain observations 
have been recorded which seem to place language in the part which is 
developed in man, and contracted in the microcephali and the ape ; Com- 
parative Anatomy, therefore, comes in aid of M. BroCa’s doctrine. 
I have reason to believe that these views of Professor Vogt 
are not very generally known in this country ; and I need 
hardly allude to the extremely important bearing they have 
upon the question at issue ; for if Professor Broca’s theory could 
be proved to be correct, — that this third frontal convolution is 
the seat of human speech,-— a strong argument could be adduced 
in favour of Darwinism. It might be said the ape possessed the 
rudiments of speech in an undeveloped form, and that in subse- 
