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REPOKT OF THE BUREAU OF ANIMAL INDUSTEY. 



sible, a vaccine similar to that employed in the prevention of anthrax. 

 Although only a preliminary step has been taken in this matter, and 

 the promise of favorable results is not nattering, we consider it best 

 to publish the results thus far obtained. 



The first step-in the process was to obtain, if possible, a cultivation 

 which should prove harmless to rabbits. This was to be accomplished 

 by placing tubes in a thermostat kept at a certain fixed temperature 

 as nearly as possible, and inoculating rabbits from time to time to 

 determine any diminution in the pathogenic activity. 



April 9, 1888. Four Salmon tubes of beef-infusion peptone were 

 inoculated from an agar-agar culture of hog cholera bacilli two 

 weeks old, and placed in a d' Arson val thermostat, the internal tem- 

 perature of which registered between 42 and 43 C. Two series of 

 inoculations were made on rabbits, one from one of the original 

 liquid cultures at different intervals, the other from a culture re- 

 newed at the end of every five days by inoculating a fresh tube. The 

 result is most easily understood by examining the following table : 



Agar culture. 

 April 9 b. i. p.* (a) 



The first inoculations were made April 19, with culture a, which 

 had been in the thermostat ten days, and culture a lf which had been 

 freshly made on April 14. Both rabbits received about -J cubic centi- 

 meter of the culture liquid hypodermically. Rabbit a v died in five days 

 with extensive coagulation necrosis in liver and enlarged spleen. Rab- 

 bit a died on the following day with the same lesions. In both hog chol- 

 era bacilli were very numerous on cover glass preparations of spleen, 

 and obtained pure in cultures. The same results were obtained in all 

 subsequent cases so that no further mention need be made of this. 



Two rabbits were inoculated in the same way April 30, one from 

 the original culture a, the other from a 3 . Both died May 4 and 5, 

 respectively. Lesions the same as with the first pair. 



Two rabbits were inoculated May 9, one from the culture a, now 

 thirty days old, the other from a B , the fifth renewal of a. Both rabbits 

 died on the 7th and the 9th day, respectively. The lesions were practi- 

 cally the same, with the addition of slight hemorrhagic lesions in the 

 intestinal tract. The period of the disease *vas slightly prolonged. 



The result was not very satisfactory, therefore, for if any attenua- 

 tion was going on its final attainment would demand too long a period 

 of time. The experiment was therefore stopped and another under- 

 taken. The temperature of the thermostat was raised to 45 C. to 

 hasten the process of attenuation. 



* Beef infusion plus 1 per cent, peptone. 



