BUEEAU OF ANIMAL INDUSTRY. 71 



made on pigs. For use in the preparation of these products 203,378 

 animals Avere inspected, 5,136 of which were rejected. 



A number of the firms licensed for the production of hog-cholera 

 virus and anti-hog-cholera serum have made arrangements to heat 

 these products in accordance with methods worked out in the bureau 

 laboratories, or by modification of such methods, and are now market- 

 ing clear, sterile virus and serum. The sterilization of these products 

 is a distinct advantage, as it removes blood corpuscles and guards 

 against contamination with the virus of foot-and-mouth disease or 

 other diseases. 



Several new products have come up for consideration during the 

 year. Among them are blackleg filtrate, prepared from cultures of 

 the blackleg bacillus on specially prepared medium, and a new form 

 of blackleg vaccine often termed blackleg aggressin, prepared from 

 juices obtained from lesions of animal^affected with blackleg. 



VESICULAR STOMATITIS. 



The event of greatest consequence during the year in the field of 

 live-stock sanitation was the appearance among horses and cattle 

 of a malady known as vesicular stomatitis. This was given peculiar 

 significance by the spread of the affection among horses collected 

 for exportation for military purposes and by its close resemblance 

 to the dreaded foot-and-mouth disease, a very extensive outbreak 

 of which had but recently been stamped out after a struggle of two 

 and a half years. 



In the early fall of 1916 reports were received from several 

 sources to the effect that a disease involving the mouths and particu- 

 larly the tongues of horses existed at the concentration remount 

 station near Chicago, 111. A careful and systematic investigation 

 was immediately begun, which indicated that at this time the disease 

 was confined solely to equines and that the infection could be traced 

 back to similar remount stations at Grand Island, Nebr., and Den- 

 ver, Colo. At these points horses and mules had been gathered 

 together by agents of the French and British Governments for ship- 

 ment abroad, and the disease found ideal conditions for its' spread 

 among the thousands of these animals closely quartered in barns and 

 pens. As the disease was undoubtedly contagious, local quarantines 

 were recommended and enforced. Sick animals were separated 

 from the well, the healthy but exposed were held for eight days 

 before beino; allowed shipment, infected pens w^ere cleaned and dis- 

 infected, and the mouths of sick animals were thoroughly washed 

 with a weak solution of permanganate of potash. 



Several w^eeks later a livery barn in Chase County, Nebr., became 

 infected as a result of the owner shipping a carload of horses to 

 Denver for Army purposes and the return to the livery barn of sev- 

 eral rejected horses. Three or four days later these rejected animals 

 developed the disease, which spread to other horses and one cow in 

 the livery barn. The disease was carried back to several ranches in 

 that vicinity by the ranch horses which had been driven to town by 

 their owners and fed and watered at this public livery barn. The 

 disease now seems to have reached its most virulent stage, and having 

 affected many of the horses on these ranches, it spread to a number 



