CLINICAL EVIDENCE OF VALUE OF SERUM 473 



than to try and save money by cutting down the dose below the 

 point of safety. 



The outbreak gives a good example of just what should be 

 done in similar cases. If, for any reason, an outbreak of hog- 

 cholera should occur after giving of the double treatment, go right 

 back into the herd with a fresh supply of high-grade serum and 

 reinject the entire herd. In the case of those animals that already 

 show signs of disease give a double dose of the serum. In this 

 manner it will often be possible to check the outbreak before it 

 gets any headway and thus save the threatened loss. In these 

 cases, unless you are absolutely certain of the quality of the serum 

 used the first time, a fresh supply of a dependable serum should 

 be secured for this second injection. Remember that where 

 cholera follows the use of the double treatment the trouble in 

 almost every case is due to the fact that the serum used was not 

 up to standard, and did not give protection against the virulent 

 blood. 



Herd Number Twenty-two. — The twenty-second herd used 

 in this series of experiments to determine the value of the serum 

 method of treatment was located near the station of the Bureau 

 of Animal Industry at Ames, Iowa. This herd also was within a 

 quarter of a mile of the diseased herd which was described as 

 Herd Number Ten in this series of experiments. 



This herd was first visited on October 19, 1907, and at that 

 time the animals seemed well with the exception of one shoat, 

 weighing about 60 pounds. A few of the sucking pigs also seemed 

 to be not just as they should. The sick shoat showed loss of 

 appetite, looked gaunt, and had evidences of some respiratory 

 trouble. With the idea in mind of preventing the possible spread 

 of the disease to other herds the entire drove was given treatment. 

 In the herd at this time there were a number of old hogs, spring 

 shoats, and also summer and early fall pigs. 



Eight old hogs were treated, each receiving 40 c.c. of the serum 

 plus 2 c.c. of virulent blood. Twelve shoats, which weighed, on 

 an average, about 125 pounds each, received about 30 c.c. of the 

 serum with 2 c.c. of the virulent blood. Thirty-three shoats, 

 weighing about 100 pounds each, received 20 c.c. of the serum 

 plus 2 c.c. of virulent blood. Seven small shoats, weighing about 



