24 ANALYTIC SECT. IV. 
SECTION Iv. 
Dermoid Irritability. 
xxx. Since Malpighi, anatomists have divided 
the dermoid system into searf-skin, rete muco- 
sum, and true skin; but the existence of the rete 
mucosum in the skin of Europeans has recently 
been questioned. 'The various tints of the human 
skin are derived from the rete mucosum, which 
are modified by the. double influence of climate 
and temperature. 
xxxiv. In the course of five or six generations, 
Kuropeans, settled in tropical climates, assume 
the colour of the aborigenes: the descendants of 
the Portuguese, who first visited the East Indies 
by sea, are now as dark as the Hindoos. But 
though tropical countries darken the European 
skin, yet a temperate climate does not turn a 
black skin white. The Diemenese, who enjoy 
an excellent climate, in south latitude 43°, are as 
black as the negroes of Calabar and Biafra. 
xxxv. The skin is a spongy substance, of dif- 
ferent thickness in various parts of the body; it 
is amply supplied with nerves and blood-vessels, 
and perforated in all parts by the exhalants and 


