BUREAU OF ANIMAL INDUSTRY. 119 



addition, the inspectors held personal interviews with 315,359 live- 

 stock owners, veterinarians, county agents, bankers, and others. 



In all, 93,512 farms were visited by the bureau inspectors, at the 

 request of the owners or otherwise, to observe the condition of live 

 stock and to give advice and other assistance. 



To demonstrate to veterinary practitioners and others the proper 

 technique in administering the protective serum treatment, 233,987 

 hogs were treated. 



Veterinary practitioners and others trained to administer the 

 hog-cholera preventive treatment, and working in cooperation with 

 the bureau forces, reported the treating of 5,474,685 hogs in the 34 

 States where bureau veterinarians are stationed. Since it is esti- 

 mated that less than 50 per cent of the hogs treated are reported to 

 the State and bureau authorities, it is conservatively estimated that 

 the treatment was administered to more than 12,000,000 hogs in the 

 United States during the year. A notable effect of the year's work 

 during the past year has been the great increase in the use of serum 

 by hog owners. 



PATHOLOGICAL DIVISION. 



The scientific investigation of animal diseases has been, as here- 

 tofore, the principal work of the Pathological Division, under the 

 direction of Dr. John S. Buckley, chief. In addition, the division 

 has studied the poisoning of live stock by plants, has aided in the 

 supervision of viruses, serums, and other stock remedies, and has 

 carried on certain routine work relating to diseases of animals. 



INFECTIOUS ABORTION. 



The study of infectious abortion has been continued in an effort 

 to acquire further information that may be advantageously utilized 

 in combating this serious malady. The manner in which the dis- 

 ease is introduced into abortion-free herds is regarded as sufficiently 

 well understood to enable stock owners and dairymen by practicing 

 reasonable precautions to keep healthy herds clean; but the control 

 and elimination of the infection after it has made its appearance 

 continues to be a perplexing problem. 



Increased interest has more recently been manifested in methods 

 of artificial immunization as a result of experiments conducted by 

 English investigators where promising results followed the employ- 

 ment of a living abortion-organism vaccine administered shortly 

 before the animals were bred. A considerable amount of experi- 

 mental work has been conducted along similar lines during the last 

 two years. When a limited number of susceptible animals were 

 utilized in an experimental capacity the results strongly indicated 

 that protection could be conferred, but when the same method was 

 applied to upward of 600 animals in an infected herd only a very 

 slight reduction in abortion losses was accomplished. Results have 

 indicated that only susceptible animals derive possible benefit from 

 the method, no decrease in losses having resulted from the treatment 

 of animals giving positive reactions. While the results obtained 

 under ex|)erimental and herd conditions were somewhat contradic- 

 tory, sumcient evidence that immunity was conferred in some in- 

 stances was obtained to justify further immunizing investigations. 



