4o8 
THE ANTIQUITY OF MAN 
very primitive human state. It is true that it is more 
depressed, more excavated, as it approaches the fissure of 
Sylvius than it is in modern brains, but this compression 
is due, as I suppose, to the massive buttress of bone 
whick apparently pressed within the commencement of 
the fissure of Sylvius. If our present conception of the 
function of the orbital part of the third frontal convolu- 
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Fig. 147. — Profile drawing of the brain cast taken from the reconstruction of the 
Piltdown skull by the Author. It is represented half size and set within a 
standard frame of lines which permits direct comparison between the various 
drawings given here. The positions of the sutures between the containing 
bones are indicated. The missing parts are stippled. 
tion is well founded, namely, that it takes a part in the 
mechanism of speech, then we have grounds for believing 
that the Piltdown man had reached that point of brain 
development where speech had become a possibility. 
When one looks at "the jaw, however, and the projecting 
canine teeth, one hesitates to allow him more than a mere 
potential ability. 
It is convenient now to direct our attention to the 
