MICROSCOPIC ANATOMY OF CANCER. 



419 



Fig. 99. — Section of epithelial cancer from palate of the ox, showing large 

 flattened cells, with numerous smaller ones enclosed in a fibrous matrix. 250 diam. 



Cancer in the domesticated animals may be classified as hard, 

 soft, epitlielial, and black. 



HARD CANCER, OR SCIRRHUS, 



Is dense and white in its structure, arranged in masses, with 

 projections passing from its centre to various parts of the organ 

 which it attacks. It cuts up almost like cartilage, and after 

 being cut the surfaces both become concave, and the haemorr- 

 hage from them is uniform, without jet, and more excessive 

 than from the surrounding tissues. It differs from a simple 

 tumour by being more rapid in, its growth, by its tendency to 

 involve the lymphatic glands, to break through the organ in 

 which it is developed, and to involve neighbouring textures. 

 When developed in the mouth and face, it interferes with the 

 process of mastication, and causes the animal rapidly to lose 

 flesh ; but when it is so situated as not to interfere with any of 

 the animal or vital functions, it does not seem to affect the 

 constitution for a long period, or until ulceration has taken place. 

 The ulcer then involves the adjacent parts, and a fungus is 

 thrown out, haemorrhage occurs, and the patient suffers from 

 irritation and exhaustion. 



