THE SKIN. 



319 



responding indentations on the corium. Succeeding the single row of col- 

 umnar elements, the cells of the stratum germinativum assume a pronounced 



Stratum corueum 

 Stratum lucidum 



Stratum 



granulosum 



Stratum 



germinativum 



FIG. 363 Portion of preceding section, showing layers of epidermis in more detail ; only the deeper part 

 of the epidermis is represented. X 280. 



polygonal form, but become somewhat flatter as they approach the stratum 

 granulosum. The number of layers included in the germinal stratum is not 

 only uncertain, but varies with the relation to the papillae, being greater 

 between than over these pro- 

 jections. The finely granular 

 cytoplasm of the cells of the 

 stratum germinativum contains 

 delicatey^r/Y/^, which radiate 

 from the nucleus towards the 

 periphery. The fibrillse are 

 not confined to the cells, 

 but extend beyond and pass 

 across the intercellular clefts as 

 delicate protoplasmic bridges 

 (Fig. 364). 



The stratum granule- Intercell c u 1 1 e a f [ 

 sum is exceptionally well 

 marked on the palms and soles 

 and in these localities includes 

 from two to four rows of polygonal cells, that stand out conspicuously in 

 stained sections by reason of the intensely colored particles of keratohyalin 

 within their cytoplasm. The nature of this peculiar substance, deposited 

 within the body of the cells as particles of irregular form and size, is still 

 uncertain. It is probable that keratohyalin is in some way derived from 

 disintegration of the cytoplasm and represents an initial stage in the process 

 ending in cornification of the succeeding layers of the cuticle. 



Fibrillae 



FIG. 364. Horizontal section, showing intracellular fibrillae 

 within cells of stratum germinativum. X 800. 



