40 TEKMINATIONS OF INFLAMMATION. 



nuclei, the so-called mucus corpuscle. 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 ; whilst mucus and pus corpuscles, 

 under all circumstances, remain round. Even from this circum- 

 stance may be derived an explanation of the fact that, whilst 

 the epithelial cells which cover and are in close opposition to 

 one another, acquire a certain firmness of cohesion, mucus and 

 pus corpuscles, which lie but loosely one against the other, and 

 are of a spherical shape, retain a great degree of mobility, 

 and are easily displaced. It has been said that mucus cor- 

 puscles are nothing more than young epithelium. Another 

 step, and pus corpuscles would be nothing more than young 

 mucus corpuscles. This is a somewhat erroneous notion. It 

 cannot be maintained that a cell which, up to the point when 

 it becomes a so-called mucus corpuscle has preserved its form 

 as a spherical body, is still in a condition to assume the typical 

 form of the epithelium, which ought to exist in the part ; and 

 just as little can it be said that a pus corpuscle, after it has 

 developed itseK in the regular manner, is capable of again 

 entering upon a course of development calculated to produce 

 a relatively permanent element of the body. The cells in which 

 the development of epithelial, mucus, and pus cells originate 

 are young forms, but they are not pus corpuscles. In pus, 

 every new cell at a very early period sets about dividing its 

 nucleus. After a short time the division of the nucleus reaches 

 a high pitch without any further growth on the part of the 

 cell. In mucus, the cells are wont merely to grow, and in 

 some instances to become very large; but they do not pass 

 certain limits, and, above all, they do not assume any typical 

 form. In epithelium, on the contrary, the elements begin 

 even at a very early period to assume their peculiar form; 

 for " what is to become a hook right early gets a crook." The 

 very youngest elements, however, which are found in pathological 

 conditions, cannot be called epithelial cells, or at least they have 

 as yet nothing typical about them, but are indifferent formative 

 cells which might also become mucus or pus corpuscles. 



Pus, mucus, and epithelial cells are therefore pathologically 

 equivalent parts, which may indeed replace one another, but 

 cannot perform each other's functions. 



