DIGESTIVE SYSTEM 123 



tine. These tumors are definitely encapsulated. It is usually not 

 possible to make a diagnosis except by autopsy. 



Of the malignant tumors, carcinoma, epithelioma, adenoma, and 

 different varieties of sarcoma have been identified. The embryonic 

 epithelial tumors may be primary or secondary. Primary epithelial 

 tumors usually have their origin in or from the mucous membrane. 

 Secondary epithelial tumors may involve any portion of the intes- 

 tinal wall and are more frequently encapsulated than the primary 

 tumors. The primary epithelial tumors, especially epitheliomas, are 

 very prone to produce necrosis of the surface mucous membrane 

 and thus cause ulceration. 



General sarcomatosis of the entire abdominal viscera is occasionally 

 observed. Sarcomas in swine are apparently not so malignant as 

 in other domesticated animals, and are more frequently encapsu- 

 lated. The appearance of the various malignant tumors in swine 

 is the same or very similar to that of the same type of tumor in 

 other animals. 



Intestinal malignant tumors, generally speaking, are evidenced 

 by unthriftiness, indigestion, emaciation, marasmus and finally by 

 death. 



Diarrhea (Dysentery) 



Diarrhea is a common symptom of a variety of diseases and con- 

 ditions. In some instances there is an apparent diarrhea without any 

 associated disease or condition. Diarrhea in young pigs — ' ' pigs scour ' ' 

 is discussed in detail on page 



Etiology. — The usual cause of diarrhea is improper diet ; moldy or 

 fermented feed and immature feed, such as soft corn, are common 

 causes of diarrhea. Sudden changes from dry to green feed or to 

 garbage is frequently responsible for the production of diarrhea in 

 swine. Diarrhea is also an outstanding symptom of diseases of the 

 digestive tract, particularly necrotic enteritis. 



Symptoms. — Diarrhea is manifested by frequent evacuations of the 

 bowel, the discharge being of a semi-fluid or fluid consistency. The 

 affected animals usually drink excessively, although their appetite 

 may be normal or only slightly altered. If the condition continues 

 the affected animals become thin and gaunt. 



Treatment. — The cause should be determined and removed. A diet 

 of relatively dry feed should be provided. The supply of water 

 should be so regulated that the affected animals get less' than the nor- 



