HOW DOUBLE TREATMENT IS GIVEN 393 



is moderate, and the protection against cholera which is given at 

 this time will last throughout the lifetime of the animal. 



These same pigs, if treated by the double method of injection, 

 keep this protection for life, as just stated, and can, accordingly, 

 be kept over for breeding purposes. The pigs which they will 

 farrow the following spring will also have a temporary protection, 

 lasting until they are about six weeks of age. It is very easy to 

 figure from this what would be the final result if we were to follow 

 this method of handling the disease. If every herd of pigs were 

 double treated at weaning time, or even earlier in case an out- 

 break of cholera be present in the neighborhood, and only treated 

 animals held over for breeding purposes, the result would be that 

 it would be almost impossible for cholera to get a start in such a 

 herd if we again treat the pigs farrowed by these immune sows just 

 before they are weaned. This is the method of handling cholera 

 which is being advocated by those who have the most experience 

 with the serum methods of treatment. 



Eradication of Cholera. — The single treatment is all right 

 when there is an outbreak already on the premises, or even where 

 the animals have recently been exposed to the disease. The double 

 method, however, is the real method of treatment that is bound 

 to produce the most desired results, namely, the driving of hog- 

 cholera out of the country. All we need do is to extend this method 

 of treatment to all the herds in the United States, and keep follow- 

 ing it up for a few years, and there will be no cholera germs in the 

 country to produce the disease. They will simply all starve to 

 death from want of any animal which they can attack. The chol- 

 era germ or no other disease-producing germ can live unless it has 

 victims to attack. By means of the double method of treatment 

 we stock the farms with a class of hogs that are so protected 

 against the disease germs of cholera that it is impossible for cholera 

 to get a start with these animals, and, as a result, the cholera germ 

 is without a place in which to keep itself alive. The germ may live 

 outside the animal body for even as long as a year, but it cannot 

 remain much longer than that time without it finds animals which 

 it can attack and thus reproduce itself. It is not believed that 

 the hog-cholera virus has the power of keeping up an existence for 

 any length of time outside the animal body. It may persist in 



