448 DISEASES OF SWINE 



alone. Fifty-nine of these received 20 c.c. each, one received 30 c.c, 

 and 2 received 10 c.c. each. Nine old sows, weighing from 250 

 to 400 pounds each, received 40 c.c. of serum and no virus. Fifteen 

 shoats and 6 old sows were left untreated to serve as checks. 



In this herd the disease proved to be of a rather mild t3^pe, as 

 neither treated nor untreated animals died very rapidly. How- 

 ever, of the 15 untreated shoats left as checks, 8 finally died. 

 There was also 13 deaths among the treated shoats. Of the old 

 hogs, both those that had been treated and those which were left 

 as checks remained well. 



While the results from this experiment are not as satisfactory as 

 in many other similar experiments, the outbreak is of interest in 

 many ways. 



In the first place, this case gives us another example of the fact 

 that young hogs are always more likely to take cholera than old 

 sows. Especially is this true in the case of the chronic or mild 

 forms of the disease. In a real severe outbreak of acute cholera 

 neither sows nor pigs are spared, as a rule, and it is not unusual for 

 this type of the disease to sweep the feed lots clean. 



It will be noted in this herd that while the injection of the 

 serum did not absolutely check the disease, yet in the animals that 

 were injected the total loss was only about 20 per cent., while in the 

 untreated animals the loss was over 50 per cent. This, too, in spite 

 of the fact that the herd was already sick at the time the injection 

 was made. 



The dose of serum given in this case was considerably smaller, I 

 think, than would be used at the present time under similar condi- 

 tions, and with a larger dose of the serum the death-rate among 

 the injected animals would, no doubt, have been much lower than 

 it was with this comparatively small dose. 



Herd Number Thirteen. — The thirteenth herd in this series of 

 experiments was located only about 20 rods from Herd Number 

 Twelve. This herd was first seen on October 15, 1907, the date on 

 which the animals of Herd Number Twelve were treated. The 

 animals at this time were all apparently well, but in danger of in- 

 fection from the other herd, which was located but a short distance 

 away. 



In this herd 5 small pigs, weighing about 25 pounds each, re- 



