spores could be washed by the rains over greater areas and would find
opportunity to develop further and form new spores in puddles of water
left on the fields, which became a culture medium by the soaking of
the dead grass. The contamination of the fields was also brought about
by spreading over them the accumulations of stable manure which
contained the discharges of the sick cattle. The tendency of the
disease to extend to lower-lying adjacent fields was due to the spores
being washed from the upper fields to the lower by the spring
freshets. Meanwhile Pasteur had discovered that by growing the
organisms at higher temperatures than the animal body, it was possible
to attenuate the virulence of the bacilli so that inoculations with
these produced a mild form of the disease which rendered the
inoculated animals immune to the fatal disease. The description of
Pasteur's work on the disease as given in the account of his life by
his son-in-law is fascinating.

Hides and wool taken from dead animals invariably contained the spores
which could pass unharmed through some of the curing processes, and
were responsible for some of the cases in man. Owing to the
introduction of regulations which were based on the knowledge of the
cause of the disease and the life history of the organism, together
with the prophylactic inoculation devised by Pasteur, the incidence of
the disease has been very greatly lessened. Looking at the matter from
the lowest point of view, the money which has been saved by the
control of the disease, as shown in its decline, has been many times
the cost of all the work of the investigations which made the control
possible. It is a greater satisfaction to know that many human lives
have been saved, and that small farmers and shepherds have been the
chief sharers in the economic benefits. The indirect benefits,
however, which have resulted from the application of the knowledge of