240 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



held as untreated controls. The milk of all these cows was tested 

 for the presence or absence of the organisms after the lapse of ap- 

 proximately 2 months, 4 months, 6 months, and 11 months. Five 

 of the treated animals and five of the controls were still carriers of 

 the microorganism when the last test was made. The 15 cows pro- 

 duced 10 seemingly healthy calves. Four were dropped by the 

 treated group of 7, and 6 by the control group of 8. One treated 

 subject and one control aborted, and the abortion organism was iso- 

 lated from the fetuses. Gestation periods of the 3 remaining animals 

 are incomplete. 



While these results reveal no information as to what bacterin 

 injections may accomplish in the treatment of abortion-free subjects, 

 they furnish a certain amount of evidence that carriers of the in- 

 fection derive little or no benefit from bacterin therapy. The fact 

 that 5 of the 8 cows which received no treatment produced healthy 

 calves, although the infection persisted in their udders, indicates, as 

 has frequently been observed, that animals may become tolerant to 

 the microorganisms to a marked degree and may readily yield mis- 

 leading data as to the value of any remedial agents that may be 

 employed if the methods of evaluation are not carefully controlled. 



The agglutination test was applied to approximately 1,500 samples 

 of bovine blood serum as a means of more definitely determining 

 the cause of abortion losses in numerous herds or ascertaining to 

 what extent the disease had become disseminated. Correspondence 

 furnished a means of acquainting many stock owners with informa- 

 tion for combating the disease. 



BABIES. 



As two Japanese investigators reported favorable results in the 

 control of rabies by a single injection of a vaccine composed of 

 fixed rabies virus that had been attenuated, and as this subject has 

 considerable importance from both economic and public-health stand- 

 points, experiments were undertaken by the Pathological Division 

 to determine the value of this method of immunization in dogs. 

 Wliile the work is not complete, suiRcient evidence has been obtained 

 to show that this method fails to protect dogs against an artificial ex- 

 posure with street virus obtained in "Washington, D. C. Some pro- 

 tection was afforded to dogs exposed to a certain virus from another 

 source. The studies are being continued. 



FEEDING MOLDS TO ANIMAXS. 



In cooperation with the Bureau of Chemistry, experiments were 

 undertaken to determine the effect of feeding oats infected with 

 various molds to horses and sheep. Oats infected with pure cul- 

 tures of Aspergillus -flavus^ A. fumigatus^ and A. tumari have been 

 fed for a period of 6 weeks each without causing any apparent ill 

 effects. The experiments are being continued with other molds. 



DIAGNOSIS OF DISEASES. 



RABIES. 



Specimens from 144 suspected cases of rabies were submitted for 

 examination, with positive results in 91 cases, comprising 78 dogs, 



