iAi;.Mi:i;.s institutes. mI 



iiijrs, but we do not kuow more about treatnieut nor uiucLi more about 

 practical preventive measures tlian ^vas IcnoAvn ten years ago. There is 

 no doubt but that proper sanitary surroundings, pure food and water will 

 do uuicli to avert the losses, but these conditions will not be provided 

 except by the few who appreciate the advantage of preventing loss. More- 

 over, these diseases can not be wholly prevented by the best hygienic 

 measures that can be provided, which tends to discourage those who do 

 try, and make others more negligent. Knowing about hog cholera is like 

 knowing about the grip— it due& nut follow tluit we can coiitrul all the 

 conditions that distribute the germs of disease. 



Two Diseases.— Hog cholera and swine plague have been made the 

 subjects of special investigation by the United States Bureau of Animal 

 Industry, and the greater part of our knoAvledge of these diseases comes 

 through this source. There is also much credit due to numerous indi- 

 viduals who have studied these affections. Hog cholera has been known 

 for a long time and is recotruized as being identical with the disease 

 called swine fever in England. Swine plague was not recognized until 

 1890. These two diseases are the cause of practically all of our great 

 losses among swine. In some outbreaks it is easy to distinguish which 

 is present, and in others the two affections may exist in the same herd. 



There is a specific germ for each of these diseases. Hog cholera is 

 caused by a germ or bacillus of hog cholera; and swine plague, by the 

 germ or bacillus of swine plague. These germs differ in size, shape, activ- 

 ity, method of growth, resistance to external conditions, and in their 

 effects upon the body. These differences are recognized by those working 

 with the disease, but of course can not be seen without the special equip- 

 ment found in laboratories. These differences may be briefly stated as 

 follows: 



The hog cholera bacillus is a small plant about 1-25,000 to 1-15,0(^3 

 of an inch long. 



The swine plague bacillus is only about one-half of this size. 



The hog cholera bacillus is shaped like a short cylinder, rounded at 

 each end. and has a number of delicate projections from the sides and 

 ends like hairs. 



The swine plague germ is oval and smooth. 



The hog cholera germs have distinct movement. 



The swine plague germs have no movement. 



The hog cholera germs stain uniformly. 



The swine plague germs will stain only at each end. 



Hog cholera germs will live in the soil from two to three mouths. 



Swine plague germs will live from four to six days. 



Hog cholera germs will live in water from two to four months. 



Swiue plague germs will live only from ten to fifteen days. 



\\h('n iiogs are fed iiixtu cholera germs they will become diseased. 



