GLANDS OF THE ORAL CAVITY. 37 



be identical, but sometimes to contain mucus (submaxillary and 

 particularly the sublingual), sometimes to want it (parotid). 



[We may take this opportunity of making some obser- 

 vations with respect to the salivary, or mucous corpuscles, of 

 authors; rounded cells of O005'", with one or many nuclei, 

 which are always to be met with in the fluid of the mouth, 

 and are usually supposed to be derived from the mucous or 

 salivary glands, yet wrongly, since the examination of both 

 these kinds of glands, and of their ducts, teaches us that they 

 excrete no formed elements. In my opinion the mucous cor- 

 puscles are nothing but products of the mucous membrane of 

 the oral cavity — not normal, although they are almost constant, 

 but a kind of exudation- or pus-corpuscles, with which they 

 have, as is well known, the closest possible resemblance in 

 structure. Many authors consider them to be abortive epithe- 

 lial cells of the oral cavity ; but in that case the epithelium of 

 the localities in which they are found must want the outermost 

 layer of large, flattened scales, which is by no means the case. 

 In my own person, at any rate, I find mucous corpuscles on 

 the gums, the lips, cheeks, and tongue, in localities in which 

 the epithelium is wholly uninjured; and by scraping with a knife 

 I can often obtain entire lamellse of epithelial plates, covered 

 with mucous corpuscles. I do not mean to affirm by this, that 

 in little sores, arising from whatever cause upon the gum, for 

 instance, where the epithelium is wholly or partly wanting, or 

 when it is lost more extensively, in consequence of disease, that 

 mucus- or exudation-corpuscles may not be developed, as upon 

 other sore surfaces, and then might be regarded as abortive 

 epithelium-cells, but only, that this does not take place in the 

 oral cavity under ordinary circumstances. I consider, therefore, 

 that the so-called mucus, or salivary corpuscles, are exudation 

 corpuscles, and consequently totally distinct from epithelial cells; 

 and I regard their formation to be analogous to that of the pus- 

 corpuscles in catarrh, which also very often takes place upon un- 

 broken epithelial surfaces. It is thus readily explained how it 

 is that they are almost entirely absent in many individuals, 

 while in others who are subject to irritation of the mucous 

 membrane of the mouth they are very abundant, and that 

 they have been observed in saliva, obtained from a fistulous 



