Xo. f)3l>] 



C ■ OL OR INHERIT. 1 NCE 



163 



than in the last of the foregoing group. Cells also now 

 appear in the lower layers with only relatively scattered 

 granules. There is an almost complete absence of gran- 

 ules from the cells of the superficial layers. There are 

 decidedly fewer pigmented cutis cells. Hair in section 

 again shows the same sort of pigment granules as above 

 described. This statement holds good for hair wherever 

 they have appeared in these sections (not seen in the 

 samples of blond skin). 



Number 3 (Fig. 2) : The pigmented basal cells of this 

 specimen contain still fewer granules than in number 4. 

 The very small number and size of the ehromatophores of 

 the corium is striking. Here again only the cells of the 

 rete mucosum Malpighi contain the granules. 



Number 8 is almost identical with number 3. 



Number 17 is like number 8 with slightly less pigment in 

 the rete mucosum Malpighi ; but here the superficial layers 

 again contain a considerable quantity of melanin granules 

 and the melanic cutis cells are more abundant than in 

 numbers 3 and 18. 



Numbers 10 and 18 are both very like number 8, show- 

 ing only a slight decrease in the quantity of pigment. 



This seems the best place for a brief discussion of the 

 foregoing facts. What is the fundamental cause of the 

 difference in the degree of color of the skins described? 

 Plainly, I believe, a difference in the abundance of the pig- 

 ment granules in the basal cells of the rete mucosum Mal- 

 pighi. A densely packed mother cell of this layer gives 

 rise to two daughter cells of very similar constitution which 

 are only slightly altered as they pass to the upper layers. 

 Hence in skins where the basal cells manufacture much 

 pigment, the entire rete mucosum Malpighi, formed of its 

 descendants- the factors of desiccation and conization 



of epidermal cells ] 

 quantity of pigmen 

 initial greater quan 

 ing greater quantity 



