RELATION OF PUS AND MUCUS TO EPITHELIUM. 493 



epithelial cells only, whilst on the other mucous mem- 

 branes, as for example on that of the urethra, we see 

 enormous quantities of pus secreted, as in gonorrhoea 

 (Fig, 63) without even the slightest ulceration being pre- 

 sent 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 pro- 

 liferation 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 transuda- 

 tion of fluid, which removes the pus-cells from the surface, 

 just as in the secretion of semen the epithelial elements 

 of the seminal tubules furnish the spermatozoa, and in 

 addition a fluid transudes which sweeps them away. But 

 the spermatozoa do not arise in the 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 q/foblastema. 

 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 prolife- 

 rating epithelium. 



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

 one another, it appears that there certainly does exist a se- 

 ries 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 commonly found somewhat 

 larger, round, granular cells with single nuclei, the so- 

 called mucus-corpuscles (Fig. 11 B) ; a little further on 

 we see perhaps still larger cells of a typical form and with 

 single, large nuclei, and these we call epithelial cells. 

 But the epithelial cells are flat, angular, or cylindrical, 



third, on many serous membranes, the first, is the one pursued. Any two, or all 

 three of them, however, may of course coincide. From a MS. Note by the Author. 



