CLINICAL EVIDENCE OF VALUE OF SERUM 443 



Whenever the hogs on a farm begin to take sick without any- 

 apparent cause, such as change of feed, change of sleeping quar- 

 ters, or feeding on salt brine or oil meal, and begin to die in a few 

 days after the disease starts, it may be set down in almost every 

 case that the disease from which they are suffering is hog-cholera, 

 and the only chance of saving the herd is by the prompt injection 

 with serum. The sooner the serum is given, the greater will be 

 the number of hogs that will be saved. Every hour lost will in- 

 crease the number of animals that will die. 



Herd Number Ten. — This herd, which formed the tenth group 

 of hogs treated in this experimental series, was located in the 

 southwest quarter of Section 6, Grant Township, Story County, 

 Iowa. The herd was already in a very bad condition when first 

 seen, and the results which followed the use of serum here are most 

 pleasing. The source of the infection in this feed lot could not be 

 definitely traced, as there were no diseased herds in the neighbor- 

 hood at the time. 



This herd was first visited by men from the Ames Experiment 

 Station on October 12, 1907. The report on conditions found at 

 that time shows that 4 hogs had already died, and about half of the 

 remaining animals on the farm showed indications of being more or 

 less affected. The animals which were sick at this time showed the 

 usual symptoms of cholera. They remained in their nests, showed 

 loss of appetite, were weak in the hind legs, and many cases had 

 already developed a diarrhea. 



An old sow which had recently died was opened up and an 

 examination of the organs made in order to make sure of the diagno- 

 sis of cholera. This was very plain, as the usual changes produced 

 by cholera were in evidence. Changes in the liver and spleen, to- 

 gether with a spotting of the kidneys and the presence of ulcers in 

 the large bowel, made the diagnosis very clear. The changes, how- 

 ever, were those of the chronic type rather than the acute form of 

 the disease, and the clinical results afterward noted were those of 

 the chronic type. 



In carrying out the demonstration, 15 shoats, each weighing 

 about 150 pounds, were each injected with 30 c.c. of hog-cholera 

 serum. These 15 animals showed signs of being sick at the time 

 and were given no virus blood. Ten other shoats, which were 



