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Para. 41
or so, have certainly had a bad effect on tropical medicine. This has been
noted by many writers, and the Sanitary Commissioner with the Government in
India has referred to the matter frequently in his Annual Report—apparently
without much influence on these unfortunate popular notions.
Such notions are merely part of that curious heresy that all parasites and
"germs" are "harmless "—a most groundless belief, due to insufficient con-
sideration of the subject. The correct professional attitude toward questions of
this nature is that there is a primâ facie case against every parasite. Any
and every species of parasite should, in the interests of our patients, be held to
be harmful unless and until the contrary be absolutely proved; they are
intruders, and, therefore, their capacity for mischief is at least a presumption
which should be acted on in the absence of complete proof to the contrary. Those
who proceed on the supposition that parasites are harmless ignore the possibility,
which always exists, of their not being so, and, in consequence, subject their
patients to considerable risk ;—which, I venture to say, is incorrect medical
practice.
The stock argument against the harmfulness of parasites is that they often
occur in apparently healthy persons—an argument of the most unscientific
nature. The total sickness produced by parasites must depend on the capacity
for mischief produced by each parasite, the number of parasites, and the strength
of the patient (paragraph 29) ; and it is quite possible that considerable numbers
of some parasites may exist in strong, well-nourished hosts without causing
mischief, while the same parasites in the same or smaller numbers may kill
more weakly patients.
It is obvious that a strong, young, well-fed man will support a much larger
number of ankylostomes without inconvenience than a cachectic struggling
between life and death can. To argue that, because the first endures them with
impunity, therefore every one can do so is quite absurd. We cannot fix with
certainty the number of ankylostomes required to produce harmful effects—the
number is, in mathematical language, a function of several independent vari-
ables.
I believe that most medical men who should happen to find themselves
possessed of even a few of these entozoa would not delay in ridding themselves
of them. Our duty to our patients, then, demands that we use every precaution
to detect and expel them from those who are placed in our care.
The drift of these observations must now be obvious. We possess in the
microscope an easy and almost sure means of ascertaining the presence of anky-
lostomes—a means which must not be neglected in cases where the parasites
may by any possibility exist. And this leads me to my first recommendation :—
The dejecta of all patients in localities where anJsylostomes are present should
be examined for the ova of these worms as a routine duty.
This recommendation applies to many parts of India, to Europeans as well
as natives, to soldiers as well as civilians. Remarks as to its feasibility will be
made presently. The use of thymol as a diagnostic measure is, of course, not
generally excusable when the microscope can be used.
The question of the spontaneous extinction of the parasitic invasion in old
cases of paludism is one to which I invite particular attention because of its
bearing on treatment by quinine. Empirical practice has already discovered
that this drug is not so efficacious in advanced as in early stages of the disease.
Its effect appears to be solely or chiefly that of a poison to the parasites ; and
it is clearly unnecessary to employ it in large doses when there are no longer
any parasites remaining to kill.
What my observations on kala-azar tend to show is that this stage may be
reached very much earlier than, to judge by the continuance of fever, we may
be led to expect. In such cases, however, the fever is the febris secondaria
post malariam.
I am convinced that a similar early extinction occurs in thousands of cases
all over India—that the invasion is often nearly or completely quelled at a
time when the appearance of daily fever, sometimes of a rather severe type,
would lead us to imagine it to be be very active.
In many of the kala-azar cases in which such fever was occurring, the
absence of the parasites was proved most conclusively, not only by a failure to
find them in repeated examinations of the finger-blood, but by the fact that
L