70 MUCUS-CORPUSCLES. 



3. Mucus-corjmscles. The mucus corpuscles have already 

 beeu described as cells, iu consequence of their resemblance to 

 the cells of epithelium. They are round globules, enclosing a 

 nucleus, which is eccentrical. We already know this to be 

 the. elementary form of most animal and vegetable cells, and 

 the presence and characteristic position of the nucleus, there- 

 fore, warrant us in concluding that in this instance also the 

 globule is a cell, although an especial cell-membrane cannot 

 be distinguished. Guterbock discovered that the nucleus of 

 the mucus- corpuscle has the peculiar property of splitting into 

 two or three smaller corpuscles when acted upon by acetic 

 acid, and that the enclosing or cell-membrane is gradually 

 dissolved in the same acid. Vogel, indeed, attributes this pro- 

 perty to such mucus-corpuscles alone as have been secreted 

 by a morbid action, and to pus-corpuscles. But I have been 

 informed by Henle that the true mucus-corpuscles (of which, 

 according to him, only a very small quantity exist in healthy 

 mucus,) exhibit the same peculiarity, and that those which are 

 not affected by the acid are true epithelial cells. As I have 

 never observed any other cell-nuclei to be similarly acted on 

 by acetic acid, the fact marks the distinction between mucus 

 and pus-corpuscles and all other cells, and, according to Henle, 

 even the youngest epithelial cells do not possess this property, 

 so that the mucus-corpuscles differ distinctly from them. It 

 appears to be a characteristic of all cell-nuclei that they not 

 only are insoluble, but do not even become transparent in 

 dilute acetic acid. These, therefore, are peculiar cells, which 

 are formed in the fluid of mucus as their cytoblastema, in the 

 same manner as the yelk-cells in the fluid of the yelk-ball. 

 They become more abundant, when the cytoblastema obtains 

 a greater degree of " plasticity," as the result of irritation of 

 the mucous membrane; and as on the other hand the secretions 

 in the normal condition possess but a very small amount of 

 plastic force, and some — the urine and bile, for instance — 

 have not any ; we accordingly find in them but a very few 

 cells, or indeed none at all, save some cast-off epithelium. I 

 have not investigated the question whether the nucleus exist 

 before the cell in the mucus-corpuscles, or upon what the 

 division of these nuclei by means of acetic acid depends. 



