134 COSMIC PEILOSOPRT. Lpt.ii. 



pean exceeds that of the Australians and Bushmen by nearly 

 forty cubic inches ; and the expansion is chiefly in the upper 

 and anterior portions. 



But this parallelism between increased intelligence and 

 increased size of the cerebrum is complicated by a further 

 parallelism between the amount of intelligence and the 

 irregular creasing and furrowing of the cerebral surface. In 

 the higher mammals both the cerebrum and the cerebellum 

 are convoluted. But the convolutions do not correspond with 

 any " bumps," real or imaginary, on the external surface of 

 the skull ; they are not symmetrical on opposite sides, like 

 the fancied " organs " of the phrenologists ; nor indeed, so far 

 as the general brain-surface is concerned, do they constitute 

 elevations and depressions at all. The surface of the brain 

 does not resemble a group of hills and valleys, but rather a 

 perfectly smooth table-land cut here and there by very steep 

 and narrow chasms. A perfectly smooth lump of butter, 

 irregularly furrowed by a sharp knife held perpendicularly, 

 would present a surface like that of the human brain. Now 

 che amount of intelligence depends in some way on the 

 number and irregularity of these furrows. In the lowest 

 monodelphian mammals, as the rodents and the lowest 

 monkeys, there are no furrows, or only a few very shallow 

 ones. In the carnivora and ungulata, there are numerous 

 furrows, some of them tolerably deep, but all of them 

 symmetrically arranged. As we proceed to the higher 

 apes, we find the furrows increasing in number and depth, 

 though not yet losing their symmetry of arrangement. 

 Idiots, young children, and adult savages have these creases 

 few and regular ; and in the lower races their arrangement 

 is similar in different individuals. But in civilized man 

 the creases are very numerous, deep and irregular ; and they 

 are not alike in any two individuals.^ 



^ Phrenologists have done good service by familiarizing the unlearued 

 public with the fact that the c^uautity of mental capacity is related to tht 



