38 TERMINATIONS OF INFLAMMATION. 



columnar and stratified epithelium exists. I shall here quote 

 from Virchow, who says : — " If you follow the development of 

 pus upon the skin, when the process is unaccompanied by 

 ulceration, you will constantly see that the suppuration pro- 

 ceeds from the rete malphigi. It consists in a growth and 

 development of new cells in this part of the cuticle. In pro- 

 portion as these cells proliferate, a separation of the harder 

 layers of the epidermis ensues, and they are lifted up in the 

 form of a vesicle or pustule. The place where the suppuration 

 chiefly occurs corresponds to the superficial layers of the rete, 

 which is already in process of conversion into epithelium ; if 

 the membrane of the vesicle be stripped of, this layer usually 

 adheres to the epidermis, and is stripped off with it. In the 

 deeper layers we may watch how the cellular elements, which 

 originally have only single nuclei, divide, and how their nuclei 

 become more abundant, and single cells have their places taken 

 by several, which in their turn again provide themselves with 

 dividing nuclei. Here, too, people have generally helped them- 

 selves out of the difficulty by assuming that, in the first in- 

 stance, an exudation was poured out, which produced the pus 

 in itself, and this is the reason why most investigators into the 

 development of pus especially selected fluids which were secreted 

 from injured surfaces. It was very conceivable that, as long 

 as no doubts were entertained with regard to discontinuous 

 formation of cells, the young cells should, without more in- 

 quiry, be looked upon as independent new formations; and 

 that the notion should be entertained that germs arose in the 

 exuded fluids, and gradually becoming more numerous, supplied 

 the pus. But the matter stands really thus : — The longer the 

 suppuration lasts, the more certainly is one series of cells after 

 the other in the rete involved in the process of proliferation, 

 and whilst the vesicle is rising up, the quantity of the cells 

 which grow into its cavity is constantly becoming greater. 

 When a variolous pustule forms, there is at first only a drop of 

 clear fluid present, but nothing arises in it ; it only loosens the 

 neighbouring parts of the rete malphigi. 



" Precisely the same is the case with mucous membranes. 

 There is not a single mucous membrane which may not, under 

 certain circumstances, furnish puriform elements. But here, 

 too, a certain difference always presents itself. A mucous 



