Page 134 - My FlipBook

pies in the blood that prevent the growth of the bacteria of
these diseases, or else antidote the poisons which produce
the disease.
Now, any of these classes of immunity may be lost as
well as gained. This kind of acquired immunity may be lost
under certain conditions, and these conditions seem to relate
to strength, or the power of vitality, in a large degree. I
have seen adults have diphtheria in a number of cases. These
adults having diphtheria have generally been mothers who
have been worn out with watching, with loss of sleep and
anxiety over their children, sick wnth diphtheria. All of the
cases I have personally seen of diphtheria in adults have oc-
curred under these conditions. It is found by experiment;
upon animals that animals that are refractory to certain
micro-organisms, as anthrax, for instance, animals that can-
not ordinaarily be made to take the disease by inoculation,
can be made to take the disease if they are worn out by
overwork. For instance, put an animal upon a wheel and
force it to turn the wheel until it is exhausted; it would not
take anthrax before, but in this exhausted condition im-
munity seems to be lost, and the micro-organisms will grow
and the animal will die of anthrax. So that these conditions
of immunity may be lost in these ways.
Accidentally acquired immunity occurs by reason of having
had the particular disease. For instance, the man has small-
pox, he becomes immune from having had the disease. So
with yellow fever, so with typhoid fever and various other
diseases, usually of the group of self-limiting diseases.
Pretty much all of this group bring about what we term an
accidentally acquired immunity. This immunity is brought
about by the development of antitoxin in the blood, the de-
velopment of an antidote to the poison produced by the
organism which produces the particular disease. This is a
principle that is now so well estabhshed that we are able to
isolate and gain the particular antitoxin that brings about
this immunity. We can collect it from the blood and isolate
it and try its effect upon other animals of the same variety,
or of different species, and bring about the same results in
them by the use of this antitoxin derived from the blood.
Then we have artificially acquired immunity, and we are
becoming acquainted with it just now, many of us, through

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