WHITE SCOURS SERUM 497 



Use. Anti-Hog-Cholera Serum is primarily a prophylactic agent. 

 However, it has been used in the early stages of the disease as a 

 therapeutic agent with good results. There are two ways in which 

 it may be used. 



(a) Serum alone method. This consists in administering intra- 

 muscularly the necessary dose of serum. The immunity produced 

 thereby lasts a month to six weeks. It is a passive immunity. 



(b) Simultaneous method. This includes giving a small dose of 

 the virulent hog cholera blood along with the necessary dose of the 

 serum. These two agents are to be injected separately and into dif- 

 ferent parts of the body. This method produces a permanent im- 

 munity in all swine except sucklings. 



White Scours Serum. The specific cause of this infection still 

 seems to be in doubt. According, however, to the uniform results of 

 bacteriological studies, the disease in most cases seems to be due to B. 

 coli or one of its virulent varieties. It was with this fact in mind 

 that Jensen treated a horse with dead and living cultures of the colon 

 bacillus and prepared a serum which had a decided bactericidal 

 action. This, however, was prepared from a single strain of the 

 colon organism and consequently the monovalent serum was effective 

 only against this particular strain of B. coli. Consequently a poly- 

 valent serum was prepared, which proved much more satisfactory. 



In the preparation of polyvalent colon serum, carefully selected 

 strains of the colon bacillus are separately cultivated in bouillon at 

 37° C. Then the cultures are mixed in measured quantities and the 

 mixture is injected intravenously in horses in quantities of 0.25 to 

 0.50 mils and after each 12 — 14 days, increasing doses up to 10 — 20 

 mils. If after a certain time, the serum of the horse produces pre- 

 cipitation in a bouillon culture of a certain colon strain in the dilution 

 of 1 — 500 or 1 — 2000, it is probable that the protective serum may be 

 utilized with satisfactory results against infections with that par- 

 ticular strain. The dose of serum prepared in this manner is from 

 5 — 20 mils. 



Another white scours serum is being prepared in this country in 

 which different strains of B. abortus (Bang) is used in connection 

 with the different strains of B. coli for immunizing the horse from 

 which the serum is to be obtained. 



Anti-Streptococcus Serum. This is prepared by injecting a 

 horse with gradually increasing amounts of killed cultures of Strep, 

 pyogenes obtained from several different sources. Several months 

 elapse before the animal is ready for bleeding. The blood serum is 

 usually preserved by the addition of a small quantity of some disinfec- 

 tant. This serum may be used in cases of pyemia, septicemia and 

 suppuration due to streptococci. The dose varies between wide limits 

 of from 10 — 100 mils, depending entirely upon conditions. A poly- 

 valent streptococcus serum has been used with good results in the 



