368 MUCUS. 



means of alkalies, certain combinations with albumen and fibrin, 

 which will exhibit all the physical and many of the chemical pro- 

 perties common to mucus ? What differences, moreover, exist in 

 the properties and characters of perfectly genuine mucus, which 

 has originated from different mucous membranes ? We do not 

 here refer to the acid or alkaline reaction, or to the admixture of 

 different cells, but simply to the different capacity for exerting a 

 digestive action with acids on animal substances. But even if the 

 chemist should succeed in overcoming all these difficulties, his 

 labours would be of no avail, in consequence of the impos- 

 sibility of obtaining the fluid in a normal condition ; for this 

 juice is secreted in such small quantities on all the mucous mem- 

 branes, as long as they continue in a normal state, that only the 

 merest traces of it can be obtained. We also know how easily the 

 mucous membranes may become diseased, and how much the mucus 

 differs in these cases from the normal secretion. Daily experience 

 shows how rapidly the number of the so-called mucus-corpuscles 

 increases with the slightest irritation of the mucous membrane ; and 

 we know from the researches of Julius Vogel, that an irritated 

 mucous membrane secretes not only such corpuscles, but also an 

 albuminous, coagulable matter, however much it may be disposed 

 to form true transudations and exudations. A proper considera- 

 tion of all these circumstances furnishes an excuse for the neglect 

 of chemists towards a subject whose investigation is so desirable both 

 in a chemical and a physiological point of view. Then, moreover, 

 the question regarding the mode of formation of this juice has not 

 been decided by physiologists; for whilst in most mucous membranes, 

 special organs, the so-called mucous follicles, have been regarded 

 as the source of the mucus, there are also mucus-secreting mem- 

 branes, which are entirely devoid of these follicles, as, for instance, 

 those of the antrum Highmorianum, the frontal and sphenoidal 

 sinuses, the cavity of the tympanum, the ovula Nabothi, the synovial 

 sacs, and finally, abnormal formations, as hygroma, cysts, &c. 

 Hence the source of the mucus cannot be referred, or at least, not 

 exclusively, to the glandular organs of the mucous membranes. 

 Tilanus* drew attention to the circumstance that all these mem- 

 branes are invested with an epithelial layer, and that the epithelial 

 cells are probably integral components of the mucous juice, which 

 must therefore stand in a causal connection with these bodies. 

 But it would appear from the observations of Virchowf and Roki- 

 c * De saliva et muco, spec, inaugur. Amstelodami, 1849, p. 5675. 

 t Arch. f. path. Anat. u. PhysioL Bd. 1, S. 115. 



