koch’s method with tuberculosis. 
81 
with the bacterium with the most perfect impunity. This 
cannot be said of the chemical products of the bacteria growth. 
These, like all chemical poisons, will act again and again upon 
the same system with little difference in effect and, if a 
partial tolerance is acquired, it can only be to a limited extent 
and after long exposure to their action, as tipplers acquire a 
tolerance of alcohol, or opium or arsenic-eaters of these re¬ 
spective poisons. Kill the microphytes in the infecting bacteria 
liquids and the chemical products will act in exact ratio with 
the dose administrated, and no amount of experience with the 
poison will prevent an excessive dose proving fatal. The 
action moreover will be prompt, and if it does not produce 
fatal results at an early stage, it will gradually subside, for 
since the poison cannot multiply itself its effects must steadily 
decrease with its elimination from the system. With bacteria 
infection, on the other hand,the evil effects must be somewhat 
delayed to allow the reproduction of the germ and the pro¬ 
duction of the chemical poison, and thus the disorder of the 
system will undergo a progressive development. In another 
respect we may conceive of bacteria infection being limited 
in its evil results. If the bacteria increase slowly, the system 
will be likelv to become somewhat habituated to the influ- 
ence of the poison and insusceptible to it, so that by the time 
the disease reaches its height the system may be able to bear 
with impunity a quantity of the poison that it could not 
have tolerated had the same amount been introduced sud¬ 
denly and before the economy had become inured to its 
influence. 
“ In illustration of the separate action of the bacteria and 
their products Koch’s experiments on mice with putrid fluids 
are most instructive. * * * Koch injected putrid liquids 
under the skin of the mouse, and found, when the amount used 
had been excessive, that the mouse died in a few hours from 
the effects of the chemical poison, and that not a bacillus 
could be found in the blood within the vessels. If, on the 
other hand, a minimum amount of the putrid liquid was used, 
as by making a slight scratch with a lancet, the tip of which 
had been dipped in the liquid, and if the mouse survived the 
