TUMOES 111 



not enougli fibrous tissue being present to obliterate the 

 vascular supply by active contraction of this fibrous stroma. 

 In the slowly developing tumors the blood supply is scanty 

 -from the beginning, on being confined mainly to the periphery 

 'of the growth, having been destroyed in the central portion 

 by the rapidly forming and contracting fibrous tissue. These 

 central portions, therefore, undergo fatty degeneration and 

 break down, that is, ulcerate, provided they are located near 

 a free surface, as the skin. Since the stroma in some forms 

 of carcinomata is very limited, the blood vessels of such a 

 tumor have but little support ; thus hemorrhage into the 

 substance of the tumor or bleeding from the ulcerated surface 

 is explained. The metastatic disposition of the cancerous 

 tumors is explained by the fact that the cells proliferate in 

 the connective tissue, lymphatic spaces reaching from here 

 the nearest lymph gland (regional lymph gland). From here 

 another lymph gland is attacked, until eventually the viscera 

 ■ are reached. Whenever this occurs the general health suffers, 

 and the state carcinosis or cancerous cachexia sets in, leading 

 ■to death from impaired nutrition, by the purulent and 

 hemorrhagic discharges, involvement of important viscera, 

 most likely also helped by the absorption and diffusion of 

 septic products arising from the ulcerating carcinoma. 



Give the etiology of carcinomata. 



No positive data exist, and a great many theories applied 

 to human carcinosis are of no value whatsoever in our 

 animals. 



1. Age. Since a great many animals for economic 

 ' reasons are not permitted to reach an advanced age, little can 

 be said as to influence of age in carcinomata. In the ox, 

 therefore, very few cases, indeed, are on record. In the dog, 

 it appears that they are unknown in -those younger than two 



