172 



STATE BOARD OF AGRICULTURE. 



6. The isolation and cultivation of Bad. abortus. Since the publication of 

 the late investigations on this j^roblem much thought has been given to its 

 practical application to the study of Bad. ahorius infections in the udder 

 and in the generative organs. I feel confident that the medium and the 

 method of isolation (atmosphere of increased CO 2 tension) can 1)e improved 

 upon but little. It is true, that in the isolation of Bad. ahorius from infected 

 milk by means of gentian violet liver agar, there are occasions when a repeated 

 examination fails to duplicate the former findings. A plausible explanation 

 for these results is that there are days when the organisms are not discharged 

 from a Bad. abortus lesion in the udder (if such a lesion exists) into the milk. 

 Similar findings arc encountered in i.solating typhoid bacilli from the feces 

 of carriers or individuals during the disease process. The method of isolation 

 in this case is not condemned as a failure when succeeding examinations fail 

 to give concordant results. To demonstrate the absence or presence of 

 Bad. abortus in milk by making repeated examinations, this method is just 

 as satisfactory as the guinea pig method, and much more economical and 

 time saving. 



Two new problems have developed and are now under investigation. 

 They are : 



1. The observation of heif(>rs which Avcrc infcM-led at birth for the return 

 of the infection (Bad. abortus). 



2. Swine abortion. 



(a) Etiology. 



(b) Susceptibility to Bad. ahorius. (Bang). 



(c) Prophylactic and therapeutic measures in the control of the disease. 

 There were received during the year 238 blood samples (bovine) (exclusive 



of samples from the experimental herd) for the application of the agglutination 

 and complement fixation tests for infectious abortion of Avhich 95 or 39 per 

 cent were positive and the remaining negative to one or both tests. 



During the year the following miscellaneous specimens have been received 

 for bacteriological diagnosis. 



Three samples of feed were received from different sources and reported 

 as being the cause of the death of live stock. These samples were fed to rab- 

 bits and guinea joigs with negative results in each case.~ 



There were prepared during the year seventeen autogenous vaccines 

 for boils. Very favoral)le results were reported from their use." 



[I. Forest Huddleson]. 



Dr. H. J. Stafs(>th, Resc arch Associate, was given leave of absence for a 

 year beginning February 1st, 1920. Leave of absence was extended to July 

 1st, 1921 and he was given the title, Research Associate and Associate Pro- 

 fessor. It is our purpose to utilize the half of his time allocated to the 



