100 On Idiotism. 
to they are found in low grounds; but in all 
countries where they have been noticed, they 
have been attended with the concurring cir- 
cumstance, of a great humidity of the atmos- 
phere. . 
When circumstances thus uniform, are at- 
tended with appearances thus similar, we 
cannot withold our assent from the opinion, 
that they stand in the relation of cause and 
effect to each other. But of the manner in 
which this influence is exerted upon the con- 
stitution we are entirely ignorant, and we 
can only further contemplate it, 1m its effects. 
The dissection of the brain of young idiots 
might lead to some earlier steps in the inves- 
tigation, but Lam not aware that this has 
been done. 
In examining the heads of these individuals, 
we find them present a configuration very 
similar, to that of children labouring under 
chronic hydrocephalus, and also to the heads 
of children having early and large evolution 
of the brain; indeed it seems to be actually 
the case in simple idiotism and cretinism, 
that the cerebrum evolves itself prematurely ; 
hence we find the idiot possessing a large 
head with a small face, frequently a flat 
crown with large frontal and parietal pro- 
tuberances, all of them circumstances which 
