45
Para. 26
the disease ; while the first incidence of the invasion may produce graver effects
in the European, it is seldom we see in him the enormous hepatic and splenic
enlargements observed in the other. In short, in Europe and America we find
mostly the fevers of the early invasion ; in India, we observe more the illness of
the cachectic.
It would be strange if this state of affairs were not reflected in the writings
of European and American observers. In fact, on reading such of their classical
works as are based on the theorem of the parasite, we should imagine that a
malarial infection consists of little more than periodic attacks of ague, and the
incidents attending them. Chronic paludism is dismissed usually in a few para-
graphs.
"We have, indeed, elaborate pictures of the pathological anatomy ; but here,
again, the point of interest lies in the changes produced by the early invasion—
the distribution of the parasites, their occlusion in cells, and the deposition
and elimination of the black pigment, with, perhaps, some excursions into the
region of the anærnia and the deposition of the yellow pigment. These are,
of course, most important and interesting ; but they do not assist us much in
our consideration of the present problem. The gradual disappearance of the
parasites (and it is evident they must finally disappear in cases of recovery),
the ultimate disposal of the melanin, and the slow development of the symp-
toms and pathological anatomy as the disease progresses towards either of its
conclusions are not dealt with in nearly sufficient detail to help us here.
I have, therefore, scarcely succeeded in gleaning many illustrative instances
from the later literature on malaria (such as is based on the parasitic theorem)
which I have access to ; but I may quote a few passages. It is, of course, under-
stood everywhere that the parasites disappear, sometimes spontaneously, in
cases of recovery ; this fact requires no corroboration. It is more necessary
to emphasise the rule that they are found less and less readily as chronic cases-
advance further—though this also is pretty generally understood. Laveran
says in his latest work [25, p. 175] "when the cachectics have not had an
attack of fever for some time the examination of the blood does not reveal,
usually, the presence of parasites. Amongst those who have returns of fever we
find, on the contrary, the characteristic parasitic elements, and often in great
number." Further on [p. 275] he remarks of the same class of cases.—"The
histological examination reveals the existence of the parasites in the spleen
and often in the liver, but in much smaller numbers than in subjects who
have died of pernicious access ; it can even happen that the parasites have
disappeared completely at the moment when the alterations of the liver, spleen,
kidneys and lungs have caused death;" and again, "Histological examination
of blood taken from the heart or veins does not ordinarily reveal the presence
of the parasites which are so numerous in the blood of the individual dead of
pernicious attacks." Davidson [26, p. 198] says, " In the advanced stages of
the cachexia, parasitic forms may be entirely absent;" and [p. 190] " How far
the final cachexia is to be ascribed to the direct action of the parasites, is still
doubtful." Thayer remarks [27, p. 192].—" The condition of the blood varies
according to the nature of the case. If the cachexia be due to a continued
uncured tertian or quartan infection, we may by careful search find an
occasional characteristic parasite. Often, though, between febrile attacks
it may be impossible, on ordinary examinations, to discover any organisms. If
the infection be with the sestivo-autumnal parasite, crescentic and ovoid
forms are frequently met with." Manson, however, says [14, p. 23], " A long
standing case of recurring malaria with marked cachexia will afford the next
best opportunity" (of finding parasites). And, " The pathology of malarial
cachexia is virtually that of acute malarial disease." But he makes this im-
portant discrimination, " There may be said to be two degrees or kinds of
malarial cachexia. In one there is merely ansemia, with congestion of the portal
system. In the other there is, in addition to ansemia, organic disease of the-
abdominal viscera—of the liver, spleen, and kidneys—the outcome of long
standing congestion of these organs. These tissue-changes not only keep up
the anæmia, in spite of removal from malarial influences, but, in the long run,
inevitably progress to a fatal issue."
The reference to the fevers of chronic paludism are most obscure as re-
gards the present discussion. Laveran [p. 175] notes that the attack often