134 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



adequate faculty, and the prospect of a small attendance of students, 

 one veterinary college discontinued its sessions. One veterinary col- 

 lege in Canada was added to the accredited list. At the close of the 

 fiscal year there were 17 accredited veterinary colleges in the United 

 States and Canada and 8 in European countries. 



OFFICE OF VIRUS-SERUM CONTROL. 



The supervision of veterinary viruses, serums, antitoxins, etc., 

 under the law of 1913, was continued by the Office of Virus-Serum 

 Control, in charge of Dr. H. J. Shore until March 31, when he re- 

 signed, and since then the office has been in charge of Dr. D. I. Skid- 

 more. 



During the year licenses were issued to 81 firms for the prepara- 

 tion of 179 products for sale in interstate commerce, and 4 licenses 

 wore canceled. 



Virus and serum for the prevention of hog cholera form a large 

 part of the volume of products supervised. To determine the purity 

 and potency of the serum and the freedom of the virus from con- 

 tamination 8,480 tests of the former and 1,616 of the latter were 

 made. The production was as follows: Serum, 673,297,617 cubic 

 centimeters, of which 4,609,531 cubic centimeters was destroyed; 

 virus for use simultaneously with serum, 19,963,053 cubic centimeters, 

 of which 364,310 cubic centimeters was destroyed; virus for hyper- 

 immunization of hogs for the production of serums, 181,750,862 cubic 

 centimeters, of which 10,052,745 cubic centimeters was destroyed. 

 The quantity of serum produced was very much larger than in any 

 previous year. The demand for clear serum has increased greatly. 



There were inspected and admitted to the premises of licensed 

 establishments for use in the production and testing of antihog- 

 cholera serum and hog-cholera virus 446,800 hogs and 3,400 calves, 

 of which 1,187 hogs and 1 calf were rejected. In subsequent oper- 

 ations 25,585 additional hogs were rejected. 



EXPERIMENT STATION. 



The work of the experiment station at Bethesda, Md., in charge 

 of Dr. E. C. Schroeder, superintendent, consisting in general of ex- 

 periments relating to diseases of animals, during the past year has 

 dealt mainly with the two maladies of greatest importance in the 

 United States at this time, abortion disease and tuberculosis. 



ABORTION DISEASE. 



Particular attention was given to the subsequent abortion-disease 

 history of calves produced by infected cows. The studies are not 

 yet complete, but as far as they have gone they strongly indicate 

 that the calves born to abortion-infected coavs are no more likely to 

 abort at their first pregnancy or to show other signs of infectious 

 abortion disease than calves of abortion-free cows. This seems to 

 be in accord with various observations which point to the conclusion 

 that cattle may acquire gradually a herd immunity against' abor- 

 tion disease, so that the disease, though it may not die out entirely, 

 after a while ceases to cause serious trouble in herds into which no 



