THE NOK-CONTAGIOUS DISEASES. 205> 



over the suspicion of a cancer subject the system to 

 lowering tendencies, which render them more liable to 

 other diseases. A cancer grows from a division of its 

 own cells, and without any support from the cells consti- 

 tuting the surrounding tissue. 



Tumors are subject to disease the same as healthy 

 tissue. Aside from transmission from the blood-stream 

 and lymphatics, malignant growths may be carried 

 down the trachea, and through the ureters. The more 

 purely cellular the tumor, the more malignant the 

 growth. Neuromas, or nerve-tumors, are rare, affect 

 only the motor nerves, and are harmless except from 

 pressure or mechanical interference. Malignant tu- 

 mors are called carcinoma, sarcoma, and epithelioma. 

 Carcinoma has a framework of connective tissue the 

 same as other structures and organs, and the interven- 

 ing spaces are filled with epithelial cells. Epithelium 

 is the name given to the cells which cover the surface 

 of the body and all mucous membrane. When the con- 

 nective tissue framework is thick and the spaces are 

 filled with large cells, the cancer is hard and fibrous. 

 Sometimes there is but a small amount of connective 

 tissue framework, with a corresponding increase in the 

 epithelial cells which constitute the growth, giving it a 

 soft appearance, resembling the physical character of 

 brain-matter, hence they are called encephaloid, mean- 

 ing brain-like. 



Sometimes hard carcinomas, which grow from the 

 skin and mucous membrane, are called epitheliomas. 

 They occur on the lip, nose, tongue, stomach, etc., so 

 called because of their being located on the surface. 



