BUREAU OF ANIMAL INDUSTRY. 253 



Durino^ the year 11,353 tests were made to determine the potency 

 and purity of anti-hog-cholera serum and 2,109 tests of hog-cholera 

 virus were made to determine its purity. From November 1, 1922, 

 to the close of the year 1,287 tests of hog-cholera virus for virulence 

 were made. 



During the year 64 subcultures, including 149 strains of organisms 

 for use in the production of biological products under license were 

 collected for laboratory examination. Of these strains, 124 were 

 found to be satisfactory and 15 unsatisfactory or contaminated. 

 Ninety-one samples of products were also collected for laboratory 

 examination ; 68 were found satisfactory and 23 unsatisfactory. 



The division continued its cooperation with the Bureau of Chem- 

 istry in preventing the sale of worthless remedies for hog cholera and 

 other swine diseases. Probably the most important case receiving 

 attention was that of the successful prosecution of a company for 

 marketing an alleged remedy for hog cholera and other diseases of 

 swine for which most extravagant claims were made. The prepara- 

 tion was found to consist of a few common drugs, including a large 

 amount of arsenic, none of which possess curative value for the 

 diseases in question. 



EXPERIMENT STATION. 



The character of the work at the experiment station at Bethesda, 

 Md., under Dr. E. C. Schroeder, superintendent, was similar to that 

 of previous years and comprised independent investigations of infec- 

 tious diseases of the lower animals, investigations in cooperation with 

 other scientific divisions of the bureau, and the provision of facilities 

 for the other divisions to make investigations under normal or natural 

 farm and field conditions. 



BOVINE INFECTIOUS ABORTION. 



Infectious abortion of cattle remained throughout the year the 

 major subject of study. It is too early to say what the results will 

 be of the control measures against the disease which have been formu- 

 lated and are now being tested in several large, privately owned herds 

 of purebred cattle. It is apparent, however, that there are difficulties 

 in the way of properly carrying out on the farm measures of control 

 which seem simple enough at an experiment station. 



Attention has been given to other possible carriers of the parasite 

 of infectious abortion than cattle and swine, and this work will be 

 continued. 



Further investigations have been made on the quality and purity 

 of commercial abortion vaccines and bacterins, and investigations 

 are in progress to determine whether some modification in the prepa- 

 ration of abortion vaccines may make them more uniformly potent 

 and whether some modification in the preparation of abortion bacte- 

 rins may lead to the production of a bacterin that has some virtue. 



The investigations mentioned in last year's report, regarding the 

 recrudescence of abortion phenomena in infected herds that had ap- 

 parently become immune, when such herds are exposed to other 

 strains of the Bang abortion bacillus than those from which their 

 seeming immunity had arisen, are still in progress. Such work is 

 slow, and while it seems probable that cattle which have ceased to 



