450 DISEASES OF SWINE 



that, even if bad effects should follow, or threaten to follow, the 

 use of the simultaneous method, they can be checked by going 

 back into the herd and reinjecting with serum alone. 



Herd Number Fourteen. — This herd, which made the four- 

 teenth one injected in this series of experiments, was located 

 in the southwest quarter of Section 24, Grant Township. This 

 was in close contact with many other infected herds located in 

 this same township. 



The farm was first visited on October 16, 1907. At this time 

 the animals were all apparently in good health. The herd was a 

 comparatively small one, consisting of 27 good-sized spring shoats. 



Twenty head of these animals, weighing from 125 to 170 

 pounds, were each injected with 20 c.c. of serum, and also received 

 at the same time 2 c.c. of virus blood. The remaining 7 shoats, 

 which were of about the same average size and weight as those 

 injected, were left as checks. 



It is of interest to note that the serum used in this experiment 

 was the same as that used in treating Herd Number Eleven, in 

 which several animals got sick after injection. The virus used was 

 also the same, except there was added some blood from another 

 sick pig in order to make up enough virus to go round. 



The herd remained well, both treated and untreated animals 

 showing no change until over a month later. About November 

 20th some of the check shoats showed loss of appetite. On Novem- 

 ber 26th 3 or 4 of these checks showed unmistakable hog-cholera 

 symptoms. One of the treated shoats on this date appeared to 

 be a little off feed, but did not show any definite symptoms of 

 hog-cholera. 



The final report on this herd was made on December 18th. 

 An examination of the herd at this time showed that 4 of the checks 

 had died, one was very sick, and another one was sick, but showing 

 signs of improvement. The seventh check shoat had been butch- 

 ered by the owner for meat soon after the herd was treated and 

 before there had been any appearance of disease in the herd. 



Seven of the animals which had been treated were also sold 

 between the time of injection and the appearance of the first 

 symptoms of the outbreak. The other 13 treated animals had 

 remained perfectly well and were in good condition at this time. 



