78 
JAMES LAW. 
causation by living 1 germs, and so late as 1879 such an accom¬ 
plished observer as Dr. Lewis argues for the absence of living 
germs in septicaemia on the ground that septicaemia poisoning 
can be produced by these purely chemical products. 
But the permanence of this theory was impossible. Chau- 
veau, Bert and Toussaint showed in the case of anthrax that 
the filtration of the virulent liquids through an unglazed 
earthenware filter rendered the filtrate non-infecting, while 
the solids retained in the filter retained their full potency. 
They further demonstrated that an overdose of the filtrate 
was speediy fatal, killing the animal in twelve hours, while a 
dose of the solids left on the filter did not kill until after thirty 
hours. Here we had at once the prompt poisoning by an ex¬ 
cessive dose of the chemical poison, and the slower poisoning 
by the implanting of the anthrax germ and the slow produc¬ 
tion and increase within the system of the same chemical 
poisons as the germ grew and multiplied. Koch has obtained . 
similar results with putrid flesh inoculated on mice. 
To those who had been following the course of experimen¬ 
tation, the field was now clear for a further advance, and such 
further advance had, indeed, become inevitable. A number 
of facts and observations testified that it was to the chemical 
poisons we must look for the direct toxic agents, while the 
microbes acted mainly as the producers of such deleterious 
chemical products. In many cases like cowpox, the microbe 
might be confined to a circumscribed area of tissue, but the 
soluble chemical products pervaded the whole system and 
rendered every tissue immune from future attack. In some 
cases, indeed,—as in cattle lung-plague—the blood had been 
proved to be fatal to the germ, while this remained confined 
to the part, tail or lung, where it had been implanted, but, in 
case of survival, no tissue in the body would thereafter fur¬ 
nish a favorable field for its inoculation and growth. 
It was inevitable that the next step should be taken—that 
of applying the devitalized chemical products of the microbe 
of a specific disease to render the system proof against such 
disease; and it was natural that Toussaint should be the first 
to enter the field. Devoted as he was to this line of experi- 
