1904.] Connection with Chloroformed Calf Vaccine. 345 



two portions. One portion after emulsification with water was 

 subjected to the chloroform process and, after elimination of its 

 extraneous micro-organisms, the chloroform was partly removed by 

 the passage through the emulsion of a stream of sterile air. The 

 other portion was emulsified with 50 per cent, of glycerine and water 

 solution. These chloroformed and glycerinated emulsions were, 

 within 24 hours of their collection from the calf, each sub-divided into 

 five parts, one part of each being stored at 10° C, 20° C, 25° C, 

 30° C, and 37° C. The potency of these several parts was subsequently 

 tested on calves at regular intervals of time. The result showed : 

 (a) that the highest potency was retained for the longest time, alike 

 for the chloroformed and glycerinated portions, by the emulsions 

 stored at 10° C, and for the shortest time, alike again by both portions, 

 by emulsions stored at 37° C. ; and (b) that the potency as between 

 the chloroformed and glycerinated vaccine kept at any one of the 

 foregoing temperatures was practically the same, the only marked 

 difference occurring in case of the vaccines kept at 37° C, a temperature 

 at which the chloroformed emulsions retained potency for a longer 

 period than did the glycerinated emulsions. 



Upon the completion of the foregoing experiments, a further number 

 of vaccines collected from vesicles of good average quality were 

 emulsified with water in the proportion of one part by weight of pulp 

 to two parts by weight of water, and subjected as before to the 

 chloroform process. When elimination of their extraneous bacteria 

 had been effected, part of the chloroform was removed from the 

 emulsions and these were placed in the ice chest at 10° C. Immediately 

 prior to the issue of these vaccines, the remainder of the chloroform 

 was removed and glycerine added in the proportion of two parts by 

 weight of glycerine to the original weight of vaccine pulp. These 

 vaccines were later, after passing the requisite tests, issued for general 

 vaccinating purposes, a similar interval being allowed to elapse 

 between their collection from the calf and subsequent issue as is usual 

 at these laboratories in the case of glycerinated vaccine, namely, about 

 6 weeks. In the case of two of these chloroformed vaccines an 

 interval of 2 months elapsed between collection and issue. 



The use of these chloroformed vaccines has been attended with 

 results showing high " case" and "insertion" success. 



Summary. 



Experience of the further use of the chloroform process in the 

 preparation of a large number of vaccines during the past year 

 confirms the conclusions arrived at in a former paper.* And mean- 



* Loc. cit., 1903. 



