106 ANNUAL EEPORTS OI' DEPARTMENT OP AGEICULTUBE. 



Many animals treated with bacterins have been tested at frequent 

 intervals following the treatment in an endeavor to determine 

 whether the injection of heavy suspensions are more efficient than 

 those less dense in causing the development of agglutinins and com- 

 plement-fixing bodies. Eesults have shown that animals receiving 

 the same treatment respond in a variable manner, indicating that 

 individuality plays an important part. Heavy suspensions have 

 usually been found more efficient in increasing the agglutinating 

 properties of the serum, however, as well as in prolonging the react- 

 ing period. Whether immunity is conferred, and whether the serum 

 reactions may be utilized for estimating the degree of immunity, is 

 yet to be determined. 



Three samples of blood serum from buffalo cows of the Yellow- 

 stone National Park herd were received with the request that the 

 serum tests for abortion be applied. Two of the animals had aborted. 

 Serum from these gave positive reactions with an agglutination fluid 

 prepared with the Bacillus aho7'tus Bang. The third case was nega- 

 tive. It thus appears that the bacillus mentioned is pathogenic for 

 this species of animal. 



ANTHRAX INVESTIGATIONS. 



Experiments with anthrax serum demonstrated that the immuniz- 

 ing and curative principle can be obtained in a more concentrated 

 and refined form through fractioning of the serum with ammonium 

 sulphate, as is done in the case of diphthei'ia and tetanus antitoxins. 

 The results of this work are contained in a paper entitled " Immunity 

 Studies on Anthrax Serum," published in the Journal of Agricul- 

 tural Research, volume 13, No. 2. 



During the year some experiments were undertaken to determine 

 the value of bichlorid of mercury in the disinfection of anthrax- 

 infected hides. Several infected hides were treated with different 

 strengths of bichlorid solution- and subsequently put through the 

 regultir tanning process. Samples for laboratory examination were 

 taken every 24 hours during the time the hides were in the bichlorid 

 solution and in the subsequent lime or lime and sodium sulphid 

 solution, a total of 11 days. The results obtained were similar to 

 those recorded hereafter by the Biochemic Division. 



Laboratorj^ examinations for the diagnosis of anthrax have been 

 made from time to time of specimens received from various sec- 

 tions of the country. A considerable quantity of anthrax serum and 

 spore vaccine has been prepared and furnished to various State 

 live-stock officials for use in outbreaks of the disease. Anthrax 

 serum has been supplied for the treatment of a number of cases of 

 the disease in man with very satisfactory results. 



VESICULAR STOMATITIS. 



Microbiologic investigations of vesicular stomatitis have failed 

 to shed any light on its ctiusative agent. Repeated cultural studies 

 of fresh vesicular fluid drawn under aseptic precautions from ex- 

 perimentally infected horses and from field cases have resulted in 

 the isolation of a variety of microorganisms, including micrococci, 

 several short rod-shaped bacilli, some of which take bipolar stain, a 

 large Gram-negative spore-bearing rod, and a fungus. Horses and 



