Prevention of Splenic Fever, ^-c, at the Broitm Institution. 277 
sirable, in order to have the full effect of such modification, 
either to inoculate directly from the guinea-pig or from a culti- 
vation not far removed from it. But there would be many 
practical advantages, if it were found that, having once trans- 
mitted the virus through one guinea-pig or a series of them, its 
modified property were subsequently maintained in the artificial 
cultivations. I have therefore kept this in view, and have 
tested the effect of successive generations of the artificially pre- 
pared poison. 
It would have been a great advantage if I had been able to 
test, side by side with these cultivations derived from the 
guinea-pig, other cultivations derived direct from a bovine 
animal. But in every case cultivations from the latter have 
failed, owing to the commencement of decomposition in the 
material sent to us. 
The method of artificial or fractional cultivation is now 
well-known. The bacillus is capable of growth in many- 
nutrient fluids, amongst others aqueous humour, hay-infusion, 
serum, urine, and also in many other natural and artificial 
fluids. The necessary conditions suitable for its cultivation are 
supply of nourishment and of air, a proper temperature, and the 
exclusion of sources of putrefaction in the form of germs of other 
bacteria. 
Of the various nutrient fluids, I have employed almost ex- 
clusively either aqueous humour or hay-infusion. The former 
may be readily procured from the eye of a recently killed 
animal, such as a sheep or ox. 
Of the two methods of cultivation most commonly employed, 
cultivation in cells and in hermetically sealed tubes, I have 
employed chiefly the latter for my present purpose, as affording 
a better supply, which can be more easily preserved, and more 
readily used for inoculation. 
The method of cultivation is very simple. A piece of glass- 
tubing about ;i-inch in diameter is drawn out at both ends to a 
fine capillary tube, and sealed at the ends. The central chamber 
thus formed, about an inch in length, is half-filled with the 
cultivating fluid, after opening the tube ; the lower end is then 
re-sealed ; a capillary tube, containing a minute quantity of the 
blood, or only rubbed on the spleen of the animal which has 
died of anthrax, is passed down into the chamber till it touches 
the cultivating fluid ; it is then rapidly withdrawn and the 
tube sealed up. The cultivating tube is then placed in an 
incubator, which is kept at a uniform temperature of about 
35° C, and left there for twenty-four to forty-eight hours, at the 
end of which time an opalescent mass consisting of the growing 
bacillus has been formed. From this a minute quantity is 
