1903.] Chloroform in the Preparation of Vaccine. 3 



organisms succumb in their turn after further application of the 

 process. 



By contrast, elimination in like degree of the extraneous micro- 

 organisms of vaccine by the glycerine process rarely occurs before the 

 fourth week after mixture, and is frequently not complete until a 

 much later period, as shown by similar plate cultures. 



After elimination of extraneous bacteria from chloroformed vaccines, 

 the chloroform is evaporated until no trace remains. Such evaporation 

 is most quickly effected by passing a stream of sterile air through the 

 emulsion. 



By the above method vaccine can be brought under the influence 

 of the germicide for such time only as suffices to kill the extraneous 

 micro-organisms. At present, however, there is no evidence to show 

 that more prolonged contact with 1 in 200 watery chloroform solution 

 has any harmful effect on its potency. 



As in the case of glycerine, non-spore-bearing bacteria in vaccine 

 lymph are alone killed by this process. But in some thousands of 

 vaccines examined at the Government Lymph Laboratories, the only 

 spore-bearing organisms found in vaccine were the strictly non- 

 pathogenic organisms of the mesenteric group Bacillus mesentencus 

 mlgatus, Bacillus mesentericus fuscus, Bacillus mesenteries ruber, Bacillus 

 mUilis and equally non-pathogenic moulds such as Penicillium 

 fjlauciim. 



The practical working value of the foregoing method has been 

 clearly shown by results of vaccinations performed with vaccines which 

 have been thus subjected to the action of chloroform. These vaccines, 

 having been rendered free from extraneous micro-organisms, were first 

 tested on calves and found to give excellent results. Within a fortnight 

 after collection from the calf and of subjection to the action of chloro- 

 form water, such vaccines have been used (after evaporation from 

 them of all chloroform) for primary vaccinations and re- vaccinations 

 with results of high " case " and " insertion " success. 



It would seem, therefore, that the following considerable advantages 

 are to be gained by the use of the chloroform process : 



(a) So speedy an elimination of extraneous micro-organisms is 

 attained that vaccine, practically free from such organisms, can be 

 distributed for use within a few hours of its collection from the calf. 

 In times of urgent demand for large quantities of vaccine, such as 

 occur during small-pox epidemics, this process must needs prove of 

 great value, since the necessity for wasting some weeks for elimination 

 of extraneous organisms by glycerine will be done away with. 



(b) In so far as the vaccination value of vaccine depends on the 

 activity of a living organism, deterioration of that value must occur 

 in the course of a longer or shorter time. The potency of some 

 vaccines, glycerinated or otherwise, becomes greatly impaired within 



B 2 



