PIGMENT. 
207 
FIG. 156 . 
ill order to show the nucleus and the granules, the 
portion B is magnified six hundred diameters. 
I shall next describe the pigment developed in the 
skin, but must first state, that, until the last few years, 
a coloured layer, distinct from the cuticle, and termed 
rete mucosum, was supposed 
to exist in the skin of the 
Negro ; a similar layer was 
subsequently found in the 
skin of the white man, but 
devoid of colour. In two 
preparations by Hunter, the 
one, the skin of a Negro, re- 
presented by a a , in Fig. 156, 
in which, in addition to the 
cuticle 6, the black layer, c, 
termed rete mucosum , is shown ; while in the other, 
which is the skin of a European, a similar layer, un- 
stained with pigment, is turned down ; these layers, 
however, are nothing more 
than the last formed portions 
of the cuticle. 
The vertical section of the 
skin of a Negro, Fig. 157, 
serves to show that not only 
the cells, but the pigment 
also, is most abundant in the 
Vertical section of cuticle of 
the Negro , showing that the last deepest layer, and, as you 
formed cells contain most pig- . . r 
men t. ascend towards the tree sur- 
A portion of the skin of a 
Negro: a a, cuticle; b, portion of 
cuticle reflected ; c, layer termed 
rete mucosum ; d, true skin. 
FIG. 157 . 
