104 Missouri Agricultural Report. 



the simultaneous inoculation of swine with certain quantities of the 

 serum (20 to 60 c. c.) and of virulent blood (1 to 2 c. c). 



At the request of Dr. Melvin, Chief of the Bureau of Animal 

 Industry, we have been co-operating with the Department in put- 

 ting this method to a practical test; and it is to this work that I 

 shall now call your attention: 



To carry out our experiments properly it was necessary to 

 secure hogs that were susceptible to the disease and were in a 

 healthy condition. We bought in the latter part of September a 

 lot of pigs, 41 in number, that were raised on a farm that is well 

 isolated from the main highways over which hogs are driven and 

 hauled to market; and is thus well situated to avoid an invasion 

 of the disease. The owner claimed that hog cholera had not been 

 on the farm for a great many years. Moreover this farmer was 

 not in the habit of buying many breeding hogs for improvement of 

 his herd. He was content to add a male hog every two or three 

 years. By this means his herd had escaped cholera for many years 

 and was probably more susceptible to the disease than many of the 

 herds of the country. To be well assured that the hogs were 

 healthy they were kept under observation for sometime before the 

 immunizing experiments were begun. 



To test their suceptibility, and at the same time to secure fresh 

 virulent blood for use in connection with the immunizing experi- 

 ments, two of the hogs were inoculated with virulent blood that 

 had been preserved for some time in sealed tubes. Both these pigs 

 died from an acute attack of hog cholera, thus showing the prob- 

 able susceptibility of the entire lot. 



The remaining hogs were divided into four lots and placed in 

 separate but adjoining pens, with close board partitions between. 

 The north end of the pens was well sheltered and the south end 

 exposed to the sun and weather. Close-mesh chicken wire was put 

 over the exposed portion of the pens to prevent birds or dogs from 

 carrying infection out or into the experiment pens. So far as the 

 hogs were concerned the conditions of shelter, exposure, food and 

 general care were the average of those found on stock farms. The 

 test was designed to meet practical conditions. 



A summary of the results of the inoculation of those four lots 

 is as follows : 



In lot I (pen 3) 10 pigs, weighing 40 to 60 pounds, were 

 placed. October 22, 8 head were injected with 20 c. c. of serum 

 B. A. I., from hyperimmunized swine. At the same time each hog 

 was injected with 1 c. c. of fresh virulent hog cholera blood. Two 



