1901 - 2 .] Plague Research Laboratory of Government of India. 125 
each bottle the flask from which it is to be filled is shaken round 
so as to distribute the bacterial sediment equally through the fluid, 
and thus ensure an equal distribution of this valuable material 
among all the bottles of the batch. The decanters are trained at 
first with water, then with flasks of sterile broth, and not till they 
are able to decant and bottle aseptically a flask of such highly 
putrescible material, are they allowed to touch the carbolised 
Fig. 6. — Assistant Surgeons, carbolising, testing, and decanting the 
Prophylactic. 
vaccine, which, of course, is much less liable to contamination 
than the uncarbolised bouillon. To test the purity of the vaccine 
at this stage, specimens from the first and the last few drops 
taken from the flasks are dropped into test tubes containing 
10 c.c. of sterile broth. Four days after, these tubes are ex- 
amined to see whether any appearance of growth is visible or 
not, thus serving at once as a test of the sterility of the vaccine 
and as a check on the skill of the decanter. In this department — 
