THE BRAIN OF FOSSIL MAN 401 
had reached this or that mental status. The statement 
which Huxley made about the ancient human skull from 
the cave of Engis still holds good of the brain : " It might 
have belonged to a philosopher or might have contained 
the thoughtless mind of a savage." 
That is only one side of our problem ; there is another 
side. Huxley's statement refers to the average brain, 
which is equal to the needs of both the philosopher and 
the savage. It does not in any way invalidate the truth 
that a small brain with a simple pattern of convolutions 
is a less capable organ than the large brain with a complex 
pattern. If, then, we find a fairly large brain in the Pilt- 
down man, with an arrangement and development of 
convolutions not very unlike those of modern man, we 
shall be justified in drawing the conclusion that, so far as 
potential mental ability is concerned, he had reached the 
modern standard. We must always keep in mind that 
accomplishments and inventions which seem so simple to 
us were new and unsolved problems to the pioneers who 
worked their way from a simian to a human estate. 
For the interpretation of the brain casts of ancient 
man we must carry with us a comparable image of a 
modern brain. The brain cast represented in fig. 145 is 
taken from the skull of an Australian native ; the capacity 
of the skull was 1450 c.c. The type specimen we are to 
use lies on the border-line between the medium and large- 
headed groups of humanity. The fissure of Sylvius is 
clearly visible on the cast ; it separates the temporal lobe 
below from the two great upper lobes — the frontal and 
the parietal.^ On the brain cast the central fissure which 
separates the frontal from the parietal lobe is indistinctly 
marked, but its situation can be fixed with a fair degree 
of certainty. A fourth lobe, the occipital, lies behind ; 
a depression represents the parieto-occipital fissure (see 
fig. 145), which marks the small occipital lobe off from 
the parietal. Below, the occipital lobe becomes united 
with the temporal lobe. 
Of those four main lobes of the brain just enumerated 
' See Appendix B. 
26 
