MUCOUS SOFTENING. 



33 



leaving the body of the cell in a very mutilated condition. This 

 simple experiment is enough to demonstrate the j^resence of 

 mucus in the interior of the epithelial cells. We are tempted to 

 see analogies between the development of mucus in the proto- 

 plasm of these cells, and the cornification of epidermic cells ; and 

 the chemical similarity between mucin and keratin yields especial 

 weight to this view. 



Then indeed the development of mucus might be conceived as a 

 mucous transformation, and we might even assume with Frericli.'<, 

 Dondersy and 0. WeheVj that a given quantity of secreted mucus 



Fig. 9. 



Softening of cartilage. Yertical section tlirougli an articular 

 cartilage in senile arthritis (malum senile articulorum), 3^^. 



represents a proportionate shedding of epithelial cells, that the 

 epithelial cells are actually shed during the development of mucus. 



I cannot give an unconditional assent to this doctrine. I 

 incline rather to the belief that the mucus is, as a rule, simply 

 extruded from the cells, and that a total transformation of cells 

 into mucus occurs only in exceptional cases (as e.g. in mucous 

 catarrh). 



§ 41. The visible phenomena attending mucous softening of 

 the matrix of cartilage are physiologically exemplified in the sym- 

 physal and inter- vertebral cartilages. Luschka has justly charac- 



3 



