388 HISTOLOGY OF THE MORBID PROCESSES. 



absorption of the products of metabolism from the tumor, rather 

 than in the abstraction of nourishment from the organism. Epi- 

 thelium, especially of the glandular form, is a tissue of great 

 chemical activity, and in carcinomata there is no special outlet for 

 the products of that activity, such as is furnished by the ducts of 

 normal glands. It may, therefore, be reasonable to infer that the 

 products resulting from the chemical activities of the epithelial cells 

 must be absorbed into the system, and that they may injuriously 

 affect the nutrition and the functions of distant organs. Carcin- 

 omata are ,also liable to undergo degenerations, the products of 

 which may be deleterious to the organism. 



A form of carcinoma which differs somewhat in appearance from 

 those that have been mentioned, though it is of essentially the same 

 nature, is the " colloid carcinoma " (Fig. 357). This variety springs 



Colloid carcinoma. (Ribbert.) The section represents a delicate stroma of areolar tissue 

 separating alveoli, which are not filled with cells, but contain the products of their 

 mucous degeneration and a few cells which have not yet undergone complete destruc- 

 tion. 



from epithelium that under normal conditions secretes mucus. 

 This function renders the cells of the cancer particularly liable to 

 mucoid degeneration, and this may be so extensive as to destroy all 

 or nearly all of the cells in some of the alveoli of the tumor, con- 

 verting them into a soft mucous mass that usually does not appear 

 quite uniform under the microscope. The epithelial cells are gen- 

 erally of columnar form, arranged, at the periphery of the alveoli, 

 with their ends in contact with the alveolar wall. This arrange- 



