SUPERFICIAL SUPPURATION. 39 



membrane is all the more in a condition to produce pus without 

 ulceration the more completely the epithelium which it possesses 

 is stratified. All mucous membranes with a single layer of 

 cylindrical epithelium (intestines) are much less adapted to the 

 production of pus ; that which is produced on them, even though 

 it has quite the appearance of pus, frequently turns out, upon 

 close examination, to be only epithelium. The intestinal 

 mucous membrane, especially that of tlie small intestines, 

 scarcely ever produces pus without ulceration. The mucous 

 membrane of the uterus, and of the fallopian tubes, though it 

 is frequently covered with a thick mass of quite a puriform 

 appearance, almost always secretes epithelial cells only ; whilst 

 on other mucous membranes, on that of the urethra, for example, 

 we see enormous quantities of pus secreted, as in gonorrhoea, 

 without even the slightest ulceration being present on the 

 surface. This depends essentially upon the presence of several 

 strata of cells, the upper forming a kind of protection to the 

 deeper ones, of which the proliferation is thus for a time 

 secured. The pus is at last either borne away by the production 

 of new masses of pus beneath it, or there occurs simultaneously 

 a transudation of fluid, which removes the pus cells from the 

 surface, just as in the secretion of semen the epithelial elements 

 of the seminal tubes furnish the spermatozoa, and, in addition, 

 a fluid which sweeps them away. But the spermatozoa do not 

 arise in this fluid ; this is only the vehicle for their onward 

 movement. In this manner we frequently see fluid exude on 

 the surface of the body without our being able to regard it as 

 a cystoblastema. If a proliferation of epithelium simultaneously 

 takes place upon the surface, the elements detached by the 

 transuded fluid will also be found to consist of nothing but 

 proliferating epitlielium." 



COMPARISON BETWEEN MUCUS, EPITHELIUM, AND PUS. 



If now pus, mucus, and epithelial cells be compared with one 

 .mother, it appears that there certainly does exist a series of 

 transitional forms or intermediate stages between pus corpuscles 

 and the ordinary epithelial structures. By the side of perfectly 

 formed pus corpuscles provided with several nuclei are very com- 

 monly found somewhat larger, round, granular cells with single 



