2 Dr. A. B. Green. On the Use of [Apr. 16, 



is solely due to the action of chloroform water. Indeed, when addition 

 of glycerine to the vaccine emulsion is desired, it can be very advan- 

 tageously effected after the completion of this process. 



The newly-made vaccine emulsion, to be subjected to the action of 

 chloroform, is dealt with in the following way : Sterile air is first 

 passed through pure liquid chloroform, whereby this air becomes 

 charged with chloroform vapour. This mixture of air and chloroform 

 vapour is then passed through the vaccine emulsion, which is contained 

 in a cylindrical glass vessel of test-tube shape, and in size suitable to 

 the quantity of vaccine to be treated. 



The mixed chloroform vapour and air can be passed seriatim through 

 a number of tubes of vaccine before it finally escapes into the outside 

 air, and it is efficient for all of them, provided that the current be 

 sufficiently strong to keep the contents of each tube in active move- 

 ment, and that a distinct smell of chloroform be apparent at the outlet 

 of the last tube of the series. 



It is essential that no liquid chloroform be allowed to pass over into 

 the vaccine, as its presence is strongly inimical to the potency of the 

 lymph. To obviate the chance of such an accident an overflow 

 bottle, weighted with sterile sand, is interposed between the bottle 

 of liquid chloroform and the tube or tubes of vaccine emulsion. 



By passage through it of chloroform vapour and air, the water of 

 the vaccine emulsion quickly becomes saturated with chloroform, and 

 this strength of solution is maintained so long as such passage is 

 continued. When saturation is reached all excess of chloroform 

 immediately escapes automatically from the vaccine. Thus the vaccine 

 is not at any time brought into contact with a stronger solution of 

 chloroform than 1 in 200 in water. 



A rapid and marked germicidal action is exerted on the non- spore- 

 bearing extraneous bacteria of vaccine thus treated. The extraneous 

 bacteria most commonly found in vaccines at the Government 

 laboratories are Staphylococcus pyogenes aureus, Staphylococcus pyogenes 

 albus, Staphylococcus cereus flavus, Staphylococcus cereus albus. Others 

 which occur either in smaller numbers or less commonly are Staphylo- 

 coccus pyogenes citreus, Proteus vulgaris, Streptococcus pyogenes, Sarcina 

 lutea, and some yeasts. Emulsions, which have contained as many as 

 100,000 extraneous micro-organisms per platinum loopful at the time 

 of mixture, have, by the action of chloroform water, become free from 

 their presence in from 1 6 hours. This freedom is evidenced by 

 absence of bacterial growth in aerobic and anaerobic plate cultures. 

 The germicidal action is first exerted on the least resistant members 

 of each species of organism present in the vaccine. Generally after 

 the first hour or hour and a half of the process, a very few of the 

 more resistant staphylococci aurtus and albus remain alive ; these 

 give rise to small inhibited colonies in plate cultures. And these 



