BUREAU OF ANIMAL INDUSTRY. ' 121 



DOURINE INVESTIGATIONS. 



The complement-fixation test has continued to be extensively em- 

 ployed for the diagnosis of dourine of horses, 46,819 samples of 

 ^erum having been tested, of which 1,143, or 2.4 per cent, gave posi- 

 tive reactions. 



Experiments are being made on drying trypanosome suspensions 

 for the purpose of preparing permanent dourine antigens of un- 

 varying titer. Out of three lots of trypanosomes dried, one retained 

 its antigenic value for one year at low temperature and in vacuum, 

 but lost all antigenic value after three months' exposure to room 

 temperature and air. 



OTHER RESEARCH WORK. 



In cooperation with the Bureau of Chemistry, experimental studies 

 wore made with a strain of Bacillus hotulinus isolated from home- 

 caimed asparagus. As an antitoxic serum effective against a strain 

 of the bacillus isolated from cheese afforded no protection to ani- 

 mals injected with toxin from the .asparagus' strain, experiments 

 are being made for the production of what is known as a polyvalent 

 serum against botulism. 



Bacteriological and biochemical studies of conditions in culture 

 n^edia and living tissue which favor the development of toxins and 

 agf>ressions by the blackleg bacillus are in progress. 



Seven cases of spontaneous tumors in white mice were examined, 

 and from this material experiments in the transplantation of tumor 

 ]^articles and the breeding of mice have been undertaken in coopera^ 

 tion with the Biochemic Division with the object of further research 

 work on tumors. 



A series of experiments with butter-coloring matters including 

 Jersey yellow, Sudan diazo-amido-benzine, etc., was undertaken in 

 cooperation with the Bureau of Chemistry, to observe the effect on 

 the skin. Microscopic studies were made of the cutaneous struc- 

 tures of experimental animals. The results proved the irritant 

 action on the peripheral as well as the deeper parts of the skin. 



Eleven samples of animal tissue and stomach contents were ex- 

 amined for poisons. In three tissues from a smelter region, zinc 

 was found in two and lead and zinc in the third. 



EXAMINATIONS FOR TUBERCULOSIS. 



Specimen tissues from 176 cattle that had reacted to the tuber- 

 culin test but in which no visible tuberculosis growths had been 

 found on ordinary post-mortem examination, were referred to the 

 Pathological Division for final diagnosis. Tubercle bacilli were 

 demonstrated in 85 cases, while none could be found in the speci- 

 mens from the remaining 91. 



GLANDERS. 



Cooperative work for the control of glanders in various States was 

 continued. The complement-fixation test was applied to 695 samples 

 of serum forwarded by various State officials and practicing veteri- 

 narians; 174 of these samples gave positive reactions to the test, a 

 per cent of 24.8. 



151352 20 9 



