DISEASES OF CATTLE 227 



With some cattle diseases, such as anthrax, rinderpest, and 

 pleuro-pneumonia, preventive inoculation is resorted to in some 

 countries. This may be desirable when certain diseases have become 

 stationary in any locality, so that eradication is impossible. It 

 should not be practiced in territories where a given disease may 

 still be extirpated by ordinary precautions. Preventive inocula- 

 tion is applicable to only a few maladies^ and therefore its aid in 

 the control of diseases is a limited one. 



When an infectious disease has gained foothold in a herd the 

 course to be pursued in getting rid of it will depend upon the nature 

 of the malady. A good rule is to kill diseased animals, especially 

 when the disease is likely to run a chronic course, as in tubercu- 

 losis. The next important step is to separate the well from the sick 

 by placing the former on fresh ground. This is rarely possible; 

 hence the destruction or removal of the sick, with thorough disin- 

 fection of the infected locality, is the next thing to be done. As to 

 the disinfectants to be used, special directions are given under the 

 various diseases. [See pages 32-45.] 



CONTAGIOUS PLEURO-PNEUMONIA. 



This disease has been eradicated from the United States, and 

 it is not probable that it will ever be seen in this country again. 



FOOT-AND-MOUTH DISEASE. 



This disease is also known as epizootic aphtha, aphthous fever, 

 infectious aphtha, eczema epizootica, and may be defined as an 

 acute, highly contagious fever of a specific nature, characterized 

 by the eruption of vesicles, or blisters, in the mouth, around the 

 coronets of the feet, and between the toes. Every appearance of 

 foot-and-mouth disease upon American soil has been quickly fol- 

 lowed by the total suppression of the disease. 



BLOOD POISONING (SEPTICEMIA AND PYEMIA). 



These two names are applied to diseased conditions which are 

 so nearly alike in their symptoms that it is sometimes difficult to 

 distinguish the one from the other. Indeed, the name pyoseptice- 

 mia, or septicopyemia, is often applied where it is impossible to 

 make a distinction between septicemia and pyemia or where each 

 is equally responsible for the diseased condition. The name septice- 

 mia is derived from two Greek words meaning poison and blood, 

 and signifies that the germ lives in the blood, hence the use of the 

 term blood poisoning for this disease. Pyemia is likewise derived 

 from two Greek words, meaning "pus" and "blood," and is that form 

 of septicemia caused by pus-producing organisms and characterized 

 by secondary abscesses. 



Causes. Neither of these diseases is brought about, strictly 

 speaking, by any specific organism, hence neither can be looked upon 

 as a specific disease. The organisms most frequently found in cases 

 of septicemia are, on the whole, the same as those of pyemia, and 

 may be either pus cocci, the bacillus coli, or other pus-producing 

 organisms. These organisms are often found as secondary invaders 

 in other diseases, such as advanced cases of tuberculosis, in which 

 cases they are responsible for the formation of pus. 



