EPITHELIAL SUPPURATION. 491 



the contrary, it is the pus which is produced as the result 

 of the proliferation of the tissue. 



The development of pus we daily see upon different 

 surfaces, both on the skin, and on mucous and serous 

 membranes. We can observe its development most 

 surely where stratified epithelium naturally exists. If 

 you follow the development of pus upon the skin, when 

 the process is unaccompanied by ulceration, you will 

 constantly see that the suppuration proceeds from the 

 rete Malpighii. It consists in a growth and develop- 

 ment 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 super- 

 ficial layers of the rete, which are already in process 

 of conversion into epithelium ; if the membrane of the 

 vesicle be stripped off, these (layers) usually adhere to 

 the epidermis and are stripped off with it. In the 

 deeper layers we may watch how the cellular elements, 

 which originally have only a single nuclei, divide, how 

 the 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 themselves out of the 

 difficulty by assuming that in the first instance an exu- 

 dation was poured out, which produced the pus in itself, 

 and this is the reason why, as you well know, most 

 investigators into the development of pus especially se- 

 lected fluids which were secreted from injured surfaces. 

 It was very conceivable that, as long as no doubts were 

 entertained with regard to the discontinuous formation 

 of cells, the young cells should without more ado be 

 looked upon as independent new-formations, and that 

 the notion should be entertained that germs arose in the 



