60 



LECTURE II. 



On examining a perpendicular section of the surface 

 of the skin, we for the most part see externally a very 

 dense stratum, of variable thickness, which at the first 

 glance is discovered to consist of nothing but flattened 

 cells, that, when viewed edgeways, look like lines. 

 They might be taken for fibres, piled up one above the 

 other, and with slight differences of level making up the 

 the whole external layer. Beneath these layers we find, 

 differing in thickness and substance, the so-called rete 

 Malpighii, and next to this, in a downward direction, 

 the papillae of the skin. If, now, we examine the 

 boundary between the epidermis and the rete, the result 

 we obtain by nearly every method of examination is, 



FIG. 16. 



Fig. 16. Perpendicular section through the surface of the skin of a toe, treated 

 with acetic acid. P. P. Extremities of cut papillae, in each of which a vascular loop, 



