104 
Pasteur and his Worh, 
mortality was very much increased. Experiment also confirmed 
the view to which this artificially infected herbage gave rise, that 
pastures become tainted by the excreta, which are often bloody, 
of living diseased animals, and by the blood and debris of those 
which have died or been killed, and buried on the spot. 
Adding some anthrax-blood to earth which had been sprinkled 
with yeast-water or urine, and keeping this at summer tem- 
perature, or at that which the fermentation of a dead body sets 
up around it- — as in a dung-heap — the bacilli of the blood had, 
in less than twenty-four hours, multiplied and developed spores. 
Afterwards these spores were observed in their latent or resting 
condition, ready to germinate and produce the disease in 
animals, perhaps years afterwards. 
To ascertain what really happens in ordinary circumstances, 
the earth from a grave in which a sheep that had died of 
anthrax from natural infection, and the carcass of which had 
been inspected by Pasteur and his assistants, was examined ten 
and fourteen months after that event, and was found to contain 
spores of the bacillus. Guinea-pigs inoculated with these 
spores died from anthrax. The same experiment was suc- 
cessfully made with soil from the surface of the grave which had 
not been disturbed since the burial of the sheep. 
Experiments were carried out with earth obtained from 
trenches, in which the carcasses of cows dead of the disease had 
been interred at a depth of more than six feet two years before. 
Material was procured from this soil, which at once produced 
the disorder. On three occasions this happened, though nothing 
of the kind was exhibited in the earth from around these 
trenches. Notwithstanding the operations of ploughing, sow- 
ing, and reaping, the surface-soil of the graves still contained 
anthrax-germs. From the carcasses of the dead animals the 
earthworms bring these germs, as well as those of putrefaction 
and others, to the surface ; and these otherwise useful creatures, 
themselves unaffected, become the indirect cause of the disease 
in animals which graze on such ground, 
M. Tisserand, Director of Agriculture in France, has re- 
marked that the malady is unknown in the Savarts of Cham- 
pagne, although this locality is surrounded by districts which 
are notoriously infected ; if it chances to appear, it is owing to 
its introduction from without. Here the arable soil is not more 
than four or five inches thick, and lies on chalk ; so that it is 
unfavourable for worms, and therefore the germs in the bodies 
of dead animals will remain in them, and the soil will not be 
tainted. It is on soils of the opposite character that anthrax is 
most likely to prevail, if anthrax-infected bodies are buried in 
them. Impressed with this knowledge, Pasteur recommends that 
