THE SKIN AND ITS ADNEXA. 22$ 



shape and character : in the deeper portion, ad- 

 joining the corium, the cells are more or less 

 cylindrical ; above this they are spheroidal or poly- 

 hedral or elongated ; still nearer the surface they 

 become flattened, and finally merge into the thin 

 cells of the horny layer. In the middle zone the 

 cells present a peculiar jagged outline, looking as if 

 they were bordered by short delicate spines by 

 which the cells appear dove-tailed together. These 

 spined cells called prickle cells are very character- 

 istic of this part of the epidermis, and are also found 

 in certain other parts of the body where stratified 

 epithelium occurs, as in the vagina, mucous mem- 

 brane of the moujh, etc. , r 



The relative thickness of the horny aud Mal- 

 pighian layers of the epidermis differs greatly in 

 different parts of the body ; in some parts of the 

 palms of the hands and soles of the feet the horny 

 layer is very thick, and here we often find that the 

 cells which lie between the horny and Malpighian 

 layers form a distinct narrow, transparent zone, 

 called the stratum lucidum. The deeper cells of the 

 Malpighian layer contain, uniformly in the negro, 

 and occasionally in circumscribed regions in white 

 men, more or less brown or black pigment. 



The epidermis forms in but few regions of the 



body a layer of uniform thickness, since the corium 



sends up into it, at varying intervals, simple or 



branching, variously shaped papillce, the valleys be- 



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