The Descent of Man

idiots, as described in Vogt's memoir. (36.
'Memoires sur les Microcephales,' 1867, pp. 50,
125, 169, 171, 184-198.) Their skulls are smaller,
and the convolutions of the brain are less complex
than in normal men. The frontal sinus, or
the projection over the eye-brows, is largely
developed, and the jaws are prognathous to an
"effrayant" degree; so that these idiots somewhat
resemble the lower types of mankind.
Their intelligence, and most of their mental
faculties, are extremely feeble. They cannot
acquire the power of speech, and are wholly
incapable of prolonged attention, but are much
given to imitation. They are strong and remarkably
active, continually gambolling and
jumping about, and making grimaces. They
often ascend stairs on all-fours; and are curiously
fond of climbing up furniture or trees.
We are thus reminded of the delight shewn by
almost all boys in climbing trees; and this again
reminds us how lambs and kids, originally alpine
animals, delight to frisk on any hillock,