NAILS. fli 



that to the innermost layer of the epidermis, very closely 

 and almost abruptly, there succeed cells, which at first 

 are also flattened, but in a less degree, and within which 

 v.ery distinct nuclei may be distinguished. These tole- 

 rably large cells mark the transition from the oldest 

 layers of the rete Malpighii to the youngest of the epi- 

 dermis. This is the point from which proceeds the re- 

 generation of the epidermis, in itself an inert mass, which 

 is gradually removed from the surface. And here is 

 also generally the boundary, at which pathological pro- 

 cesses set in. The farther we advance inwards, the 

 smaller do the cells become ; the last of them standing 

 in the form of little cylinders upon the surface of the 

 papillae (Fig. 16 r, r). 



On the whole, the relations* of the individual parts 

 throughout the whole surface of the skin are everywhere 

 the same, however manifold the peculiarities of detail 

 may be, which the individual layers offer in respect to 

 thickness, position, firmness, and connection. A section 

 of a nail, for example, which in its external appearance 

 certainly widely differs from ordinary epidermis, pre- 

 sents, nevertheless, on the whole, the same conformation, 

 and has only one essentially distinctive feature, that, 

 namely, in it two different epidermoidal structures are 

 thrust, the one over the other, and thus a complication 

 arises, which, if not duly attended to, may lead to the 

 assumption of certain specific differences between it and 

 other parts of the epidermis, whilst it really consists only 

 in a peculiar change in the position of certain layers of 



and near it little spindle-shaped, connective-tissue corpuscles, displaying at the base 

 a reticulated arrangement, may be observed ; to the left, a bulging out of the pa- 

 pillae, corresponding to a tactile corpuscle, no longer visible, and situated at * 

 deeper level. JR. R. The rete Malpighii ; immediately around the papilla a very 

 dense layer of small, cylindrical cells (r, r) ; more externally, polygonal cells, gra- 

 dually increasing in size. K Epidermis, consisting of flat and more closely packed 

 layers of cells. S S. Duct of a sweat gland passing through. 300 diameters. 



