266 APPLIED BACTERIOLOGY 



to Man. — From the brain and medulla oblongata of a mad 

 dog which has been killed or has died of rabies, there are 

 taken, under strict sterile conditions, a small piece of the 

 medulla oblongata from the floor of the fourth ventricle, 

 and also another small piece from the central canal. The 

 fragments removed should be about the size of a pea. 

 These two pieces are put into a sterile test-glass (which has 

 been sterilised for at least twenty minutes at 120° C), and 

 pounded up with a glass rod, adding about 5 or 6 c.c. 

 of veal broth. It is worked up thoroughly into an 

 emulsion, and then set aside for use. The vessel used for 



Pia. 18. — Pasteue Flask. 



preparing the emulsion in at the Pasteur Institute is an 

 ordinary conical test-glass, holding about half an ounce. 

 Before use these glasses are covered with a piece of filter- 

 paper, which is twisted round the top and sterilised, the 

 paper cover only being removed to admit of the emulsion 

 being made. It is then replaced until the preparation is 

 required for use. The broth is made by using 2 pounds 

 of lean veal to 1 litre of water neutralised with soda or 

 potash if necessary, then filtered and stored in Pasteur 

 flasks. The pipette-end being sealed in the flame, the 

 broth is poured in, and the other opening is closed with a 

 plug of cotton-wool. The flasks are then sterilised at 



