?(   52   )
sun, etc., and have no connection whatever with mosquitoes. One explanation
of their cause is that all the asexual parasites of the first infection have
not died out, and when the patient's resisting power is lessened by any of
the conditions just mentioned, the parasites are able to develop rapidly
again and produce their ill effects. Another explanation has already been
mentioned under the heading parthenogenesis. (Page 3.) In this view it is
assumed that all the asexual parasites have died out, but that some of the
sexual (female) forms, which are very resistant even to the action of large
doses of quinine, persist and that under influences similar to those just men-
tioned a crop of asexual forms can be produced from these female parasites.
The relation of the parasites to the different clinical stages.-If the patient's
blood be examined at the onset of fever, that is a little time before the cold
or rigor stage, it will always be found that (as we have already noted) the
majority of the parasites are in the stage of division or sporulation. The
onset of fever and the rigor correspond in point of time to the sporulation of
the asexual forms of the parasite. From the point of view of treatment this
is an important point to remember. By the time the hot stage approaches
all the parasites have divided up and are entering, or have already entered,
fresh corpuscles. During the last part of the hot stage, during the sweating
stage, and during the period of apyrexia, the parasites are enclosed in the
red blood corpuscles, growing and developing pigment. Between any two
similar stages of the parasite an interval of 48 hours elapses, i.e., the Benign
Tertian parasite takes 48 hours to complete its asexual cycle.
These points and the clinical characters of Benign Tertian malarial fever
are-illustrated in Chart. I.
This chart shows three typical paroxysms of ague occurring at the same
time on alternate days. Each attack lasted from about 11 A.M. until about
8 P.M. At 12 noon, during the shivering stage, sporulating forms were found
in the blood, and at 7 P.M. very young forms, which had lately entered the
corpuscles, were present. The sudden rise of the fever and its quick fall are
characteristic of Benign Tertian infections. The administration of thirty
grains of quinine at 7 A.M. on the 26th, though it did not prevent the onset
of the attack on that day, stopped all future paroxysms and practically cured
the case. (See page 72.)