468 DISEASES OF SWINE 



Herd Number Ten, previously reported. This herd was visited 

 on October 18, 1907, and at that time was apparently well and in 

 good condition. As it was desired to test the effects of the serum 

 treatment in preventing the spread of the disease from infected 

 herds, it was decided to treat this herd as a protection against the 

 possibility of spread of the disease from Herd Number Ten. 



There were 18 shoats in this herd which would average about 

 125 pounds in weight. Each of these received an injection of 30 

 c.c. of serum and, at the same time, were given 2 c.c. of virulent 

 blood. Sixteen more shoats in the herd, weighing from 60 to 90 

 pounds each, were injected with 20 c.c. of serum and the same dose 

 of virulent blood as that given to the larger animals. There were 

 no checks left in this herd. 



After-results in this herd were excellent. Not one of the 

 injected animals became sick, and they remained well and thrifty 

 throughout the balance of the season, in spite of the fact that they 

 were in close contact with a herd where the disease was present. 



The results here are encouraging. They again give us proof 

 of the fact that the double method of treatment can be given with- 

 out danger if the serum be of good quality. In this herd a total of 

 34 animals were injected. The dose of serum used was about 10 c.c. 

 smaller than that usually recommended for animals of the same 

 weight, and the dose of virus blood used was double that which is 

 now recommended for animals of this weight. Yet the results 

 were excellent. A first-class serum will protect in this dosage from 

 much larger doses of virulent blood than are ordinarily used. 

 When virus is used in the dose recommended in this book, and 

 protection given by a dose of serum of the size recommended here- 

 in, the danger is absolutely reduced to the minimum. The im- 

 munity which is produced by the smaller dose of the virus is just as 

 powerful as that produced by the larger dose. All the cells of the 

 body need is a sufficient dose of the virus to give them a thorough 

 stimulation, and they will actively take up the work of forming the 

 germ-fighting agents known as antibodies. Once the body starts 

 to manufacture these soldiers of defense against infection, the army 

 of them that will be put in the field will be far more than sufficient 

 to protect against the usual amount of infection which might enter 

 the ordinary channels of entrance. 



