OF VETERIXARY MEDICINE. 153 



PANCREAS. 



The pancreas is most commonly affected with fatty degenera- 

 tion, but that is very seldom. One of the evidences is fat in the 

 feces, probably due to faulty action of the pancreatic juice. 



The symptoms are indefinite and are not diagnostic. The 

 animal is anaemic and shows irritability anvl dic;s much emaciated 

 from collapse. 



CONSTITUTIONAL OR BLOOD DISEASES. 



A constitutional disease is one in which the whole system or 

 blood is affected primarily, and if the disease localizes itself it 

 does so secondarily. The exogenous diseases are contagious ; the 

 endogenous are non-contagious. 



The word "contagious" refers to a disease that is due to a 

 specific virus peculiar to the disease itself. The agent of the 

 disease is called the contagium. 



If an animal is affected with a contagious disease, the spe- 

 ci'iic virus of that disease inoculated into another susceptible ani- 

 mal will produce the disease. There are different means of in- 

 oculation : 



1. Artificial — scarify the skin and intro- 



duce the virus. 



2. Natural — exposure through the alimen- 



tary tract, respiratory, or through any 

 mucous membrane or abraided sur- 

 face, or accidental wound. 

 The contagium or specific virus in most contagious diseases 

 is a known micro-organism — an animal parasite (protozoon") or a 

 vegetable parasite (bacterium). In not all contagious diseases 

 has the specific virus been found. In such cases we cannot call 

 the causal agent a micro-organism, and yet we can reasonably 

 presume it to be one or else the disease would not be specific. 



As regards the difference between bacteria and protozooa, 

 Sternberg gives a concise definition: The animal organism, that 

 is a protozoon, receives food particles into the interior of the 

 body assimilating the nutritious portion, and subsequently ex- 



