114 ANNUAL REPORTS OF DEPARTMENT OP AGRICULTURE. 



have been maintained under very similar conditions. Additional 

 evidence has been obtained that susceptible pregnant heifers may 

 readily acquire the disease through the ingestion of comparatively 

 small amounts of infected material, and that nonpregnant cows as a 

 result of ingesting the infection may develop positive serum reactions 

 and eliminate abortion bacteria in their milk. 



While experimental work thus far conducted has failed to incrimi- 

 nate the bull as an actual disseminator of the disease at time of serv- 

 ice, bacteriological examinations of the generative organs of 33 male 

 animals, the blood serum of which showed some agglutinating prop- 

 erties for abortion bacteria, yielded positive results in three instances. 

 There are grounds for suspecting that bulls of this character may be 

 capable of contaminating their environment with abortion infection 

 and in this manner at least be menacing factors as disseminators of 

 the disease. 



Immunization experiments with vaccines on animals where the 

 exposure has been controlled, and also under herd conditions, have 

 been in progress for some time, but the work has not advanced 

 sufficiently to justify draw^ing any definite conclusions. 



Serological tests applied at regular and frequent intervals to the 

 blood serum of pregnant heifers to which had been administered by 

 the mouth a sufficient quantity of abortion-infected material to 

 cause them to abort later has demonstrated that a wide variation 

 exists in the period of time that intervenes before agglutinins or 

 complement-fixing bodies are elaborated. The negative period fol- 

 lowing the administration of the infection in seven cases, all of which 

 subsequently aborted, varied from three weeks to four and one-half 

 months. The fact that animals give negative serum reactions at 

 the time of removal from infected herds need not, therefore, nec- 

 essarily imply that they are not harboring the abortion organism, 

 and that they may not develop positive serum reactions and abort 

 at a considerably later period. 



EXAMINATIONS FOR TUBERCULOSIS. 



Specimen tissues from 86 cattle that had reacted to the tuberculin 

 test, but in which no visible tuberculous growths had been found on 

 post-mortem examination, were referred to the pathological labora- 

 tory for decision as to the presence of tuberculous lesions. By means 

 of microscopic examination or animal inoculations, or both, the 

 presence of tubercle bacilli was demonstrated in 63 of the samples, 

 while 23 gave negative results. 



A specimen of unusual interest, found during the regular course of 

 meat inspection, consisting of the lungs from a cow bearing lesions 

 similar to those of tuberculosis, yielded an organism which is evi- 

 dently one of the pseudotubercle bacilli and which is being studied, 



OIDIOMYCOSIS IN CATTLE. 



Experimental work on coccidioidal granuloma (oidiomycosis) has 

 been completed, and from the data obtained the following conclu- 

 sions have been drawn: The affection has been observed in cattle as 

 a natural infection of the bronchial and mediastinal lymph glands. 

 It is transmissible experimentally to guinea pigs, rabbits, dogs, cat- 

 tle, sheep, and swine. Cattle affected with the disease show no 



