THE MICROSCOPE IN PATHOLOGY. 



293 



tumor, although it may occur primarily also, as in the 

 articular ends of bones, in the eye, in the testicles, etc. 



(3.) Colloid. Alveolar or gelatinous cancer. This form 

 depends on the metamorphosis of one of the preceding 

 forms, the cells of which undergo a mucoid or colloid 

 change. It is exceedingly malignant, and may occur in 

 the stomach, large intestine, liver, ovary, or mammary 

 gland (Fig. 239). 



Fir. 239. 



Carcinoma gelatinosum. 1-300. After RINDFLEISCH. 



4. Epithelioma. Cancroid, or epithelial cancer, always 

 grows in connection \vith a cutaneous or mucous surface, 

 and its epithelial elements resemble the squamous variety 

 of epithelium so as scarcely to be distinguished from the 

 normal cell. They sometimes have more than one nu- 

 cleus, and are often flattened and distorted by mutual 

 pressure. They are not so ready to undergo fatty degen- 

 eration as the cells of other varieties of carcinoma. As 

 the cells multiply they have a marked tendency to be ar- 

 ranged concentrically in groups, forming globular masses 

 " epithelial pearls," "bird's-nest bodies," etc. (Fig. 240). 



There is little doubt as to the epithelial origin of the 



