1904]. Connection with Chloroformed Calf Vaccine. 



343 



In the first set of experiments vaccine emulsion, consisting of one 

 part by weight of pulp and two parts by weight of water, was divided 

 into several equal portions. Each portion was then submitted to a 

 pre-determined and separate temperature along with the set of 

 apparatus to be used for its treatment with chloroform. These tempera- 

 tures ranged from 10° C. — 37° C. In each case after both emulsion 

 and apparatus had reached the requisite temperature of the experiment, 

 passage of chloroform vapour and air through the emulsion was 

 effected. 



It was found by means of plate cultivations, that elimination of 

 extraneous micro-organisms was most rapidly effected in the case of 

 the emulsions chloroformed at 37° C, and that elimination was most 

 slowly effected in the case of the emulsions chloroformed at 10° C. 

 Between these temperatures the gradation of germicidal action was 

 very constant. 



The potency of these vaccines was subsequently tested by inocula- 

 tions on calves, with the result that vaccines which had been subjected 

 to the chloroform process at temperatures below 30° C. caused rather 

 better vesiculation than the vaccines treated at temperatures 

 above 30° C. 



In the second set of experiments, vaccine emulsion, prepared as 

 before, was divided into a number of equal portions, each of which 

 was placed in a separate test-tube. In this case, the emulsions were 

 all subjected to the chloroform process at 15° C. After the passage of 

 chloroform vapour and air through the emulsions for half an hour, the 

 entrance and exit of each vaccine tube were clamped in order that 

 none of the contained chloroform might escape, and the tubes were 

 placed in temperatures ranging from 10° C — 37° G. for 24 hours. In 

 the case of these emulsions, where the amount of chloroform present 

 in each must have been approximately the same, a similar gradation of 

 germicidal action was evidenced as in the former set of experiments ; 

 elimination occurring most rapidly in the case of emulsions submitted 

 to a temperature of 37° C, and most slowly in the case of emulsions 

 submitted to a temperature of 10° C. 



The potency of each of these vaccine emulsions was tested as before 

 by inoculations on calves, with the result that vaccines which had 

 been submitted to temperatures below 30° G. gave slightly better 

 vesicles than vaccines which had been submitted to temperatures 

 above 30° C. 



Both series of experiments indicate that the temperature at which 

 extraneous bacteria are killed most quickly in vaccine emulsion by the 

 chloroform process, the specific germ being left meanwhile in state of 

 full activity, lies probably between 18° C. and 23° C. 



2 b 2 



