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probably will be in the red corpuscles: a large number will be like shapeless particles
of pale red jelly, from half the size of a normal corpuscle downwards. The last change
observed will be a large number of small granular specks in the serum. I wish to
note particularly that the first apparent change in the blood is the presence of those
foreign bodies—parasites; and that the other changes mentioned do not appear in
some cases for several weeks afterwards, but that with the advent of the parasites
there is a very general constitutional disturbance:—1 st, a lowering of the temperature ;
2nd, an abnormal elevation of it; 3rd, jaundice with petechiae of the mucous mem-
branes; 4th, dropsical swellings, &c. The question suggested by these facts is,
whether the presence of the parasite is the cause of the disease, or whether the disease
is the cause of the appearance of the parasites. That they are most intimately related
to each other, is beyond reasonable dispute. There are some eminent pathologists
in India who deny the parasitic origin of specific blood diseases: they say the
cause of all such diseases, from small-pox to anthrax fever, is not any organic spore,
germ or ova or parasite of any kind, but some purely chemical agent which has never
yet been discovered, and that these organisms develop at once in blood which has been
so chemically altered, each chemical virus developing its specific organism, the spores
or ova of which are supposed to be in the normal blood ready to develop as soon as
chemistry favors them. The organisms themselves, even when developed, are supposed
by them to be harmless.
That is one of the most vexed questions of the present day in the pathological
world, and it strikes hard at the root of the science and practice of sanitation. Against
the above theory it is contended, firstly', that we should judge the unknown by the
known: this supposed specific disease virus is not known to chemistry, and there is
no known pure chemical agent that acts in any way analogous to the specific virus of
fevers, one dose of which, when taken into the stomach, gets into the blood, multi-
plies itself there a million-fold, and produces a constitutional disturbance lasting for
weeks or months ; and a few drops of that living blood, after the lapse of many weeks
since it was first chemically impregnated, if placed beneath the skin of a healthy
animal, will, by chemistry alone, multiply and reproduce the same disease again, and
so on ad infinitum. In considering this subject we must bear in mind that the same
blood does not remain long in the circulating vessels, but that it is in a constant state
of renewal; and, so far as we have any knowledge of pure chemical non-corrosive
poisons, when only one dose is given it either precipitates and remains harmless because
there is too little of it, or else it is passed out with the effete blood and leaves the
system uninjured, or else it rapidly causes death : a small dose of pure chemical poison
has never been known to multiply itself in the system faster than the excreting organs
can get it out of the blood, nor has there been anything analogous to that performed
by any ingeniously-contrived apparatus at any chemical laboratory that I am aware
of. Secondly, it is contended that specific self-propagation of like by like is the most
characteristic feature of living organisms as distinguished from purely non-vital
chemical agents; so that if we never found any foreign living organisms in the blood
of specific disease, reason by analogy from the known to the unknown would lead
us to believe that the disease was due to propagating living organisms present
in the blood, though unseen. And thirdly, it is contended that the microscope
has enabled us to see such living organisms as are efficient causes in the blood
to develop the diseases in question. In reply to this, they say that organisms so
like these as not to be distinguished by the microscope, are found also in some
healthy subjects, and appear to do no harm; therefore, we should not conclude
that the one is any more virulent than the other. The answer to that objection
is this: we must not always judge by appearances, but rather by actions. There
is an old saying (worthy of being remembered in our intercourse with men) that
the " fool is considered wise until he speaks." It is not by vision, but by
noticing results that we first learn that one snake is poisonous, and another, not very
unlike it, harmless; that one berry is a deadly poison, and another berry, very like
it, is wholesome. After we learn that, we notice the specific differences in the
appearances of the snakes and berries ; but if the snakes and the berries were so small
as some of the organisms we find in the blood, no microscope could enable us to see
the slightest difference between the poisonous and the non-poisonous. We therefore
must judge of them by their results or associations, and we do it in this manner. We