ITS ORIGIN. 377 



error presented by such means is too obvious to need further 

 comment. It is probable that the secretion is seldom perfectly 

 normal when present in excess in morbid affections of the mucous 

 membranes, and that it is generally mixed, in these cases, either 

 with a transudation or exudation. This is shown both by the 

 microscopico-mechanical and the chemical investigation of mor- 

 bidly secreted mucus. 



We have already observed, in the beginning of this chapter, in 

 reference to the origin of the mucus, that the seat of the formation 

 of this fluid is not limited to the mucous follicles, for we have 

 already noticed several mucous membranes in which there was no 

 appearance of any such glandular organs. Some facts, indeed, 

 seem to warrant the conclusion, that the formation of mucus is 

 not limited to a definite spot, or associated with any definite 

 tissue. The conversion of Wharton's gelatin into a substance 

 perfectly similar to mucus in respect to its physical and chemical 

 properties, the gradual transition of the colloid mass of many 

 cysts into perfect mucus, and its occurrence in many exudations 

 proceeding from serous membranes, are facts which cannot be lost 

 sight of in our consideration of the origin of mucus. Tilanus has 

 drawn special attention to the circumstance, that epithelial struc- 

 tures are always present wherever there is true mucus. This 

 observation might lead to the assumption, that the formation of 

 mucus is connected with the development of certain cells, that 

 is to say, that its production occurs simultaneously with the 

 development of certain morphological elements. Two views here 

 present themselves for our consideration ; one of which is, that 

 the albuminates of the liquor sanguinis become decomposed, 

 under certain hitherto unknown conditions, into the substratum of 

 the epithelial cells and into mucus, whence the latter substance 

 might in some respects be considered as a secondary product of 

 this cell-formation, so that the mucous juice in the mucus would 

 hold the same relation to the epithelial cells as the spirituous fluid 

 does to the yeast-cells in a mixture which has undergone fer- 

 mentation. The other view, which seems to be supported by 

 numerous observations made by Scherer and Virchow,* refers 

 the origin of the mucus to a partial disintegration of the epithelial 

 cells. All who have followed Frerichs in his observations on the me- 

 tamorphosis of the cells within the gastric juice, or who have exa- 

 mined them by the microscope in the preparation of artificial gastric 

 juice, will easily comprehend the gradual solution of the gastric cells 

 * In a Private Communication. 



