that it was not so severe, and that haemoglobinuria was entirely 
absent. Moreover, the whole comparatively fever-free period from 
the 1 8th to the 41st day, in which the temperature frequently 
exceeded normal, differed from ordinary malarial apyrexial periods, 
in which the temperature generally remains quite and even 
considerably below normal, and asexual parasites are often still to 
be found. Quinine certainly did not prevent the second and third 
pyrexial periods, although it was never followed by relapses in our 
cases of malaria; and the leucocytes did not show the characteristic 
diminution of malaria. 
From these facts we are inclined to infer, almost with certainty, 
that the second and third pyrexial periods were not due to the toxin 
of the parasites of malaria, that is, to the usual cause of malarial 
attacks, but to some other cause. As shown in our previous paper, 
the fact that parasites were not found in no less than forty-three 
thick film specimens does not prove by any means that none were 
present in the whole body ; but it proves that their numbers were 
much below the usual figure required to produce even slight fever. 
It, then, the later pyrexial periods were due to the small remainder 
of parasites, either the ' virulence ’ of these must have become 
suddenly and greatly exalted after the gth day, or else the patient’s 
resistance to their toxin must have, become suddenly lowered. Neither 
of these appears probable, because the general type of the fever in 
the later periods differed so much from the usual malarial type, and 
because quinine had no reducing effect. If there is another cause, 
as seems to be highly probable from this case, it must exert a 
powerful haemolytic as well as pyrogenous effect. The third 
pyrexial period is of great interest, because it appears to establish 
a new fact, namely, that this peculiar fever, though generally 
associated with a great fall of haemoglobin and also with haemo¬ 
globinuria, need not necessarily be associated with either (the 
Plasmodia being at the same time undetectable). This proves also 
’hat mere haemoglobinuria by itself does not cause the fever. 
\\e now content ourselves with merely recording the observed 
fact& without discussing the possible causes of the fever. Further 
rt searches are required to ascertain whether similar phenomena occur 
111 °^ er cases. It has been often shown since Panse’s* researches 
Otto Pans*. Zeit. fur Hygiene, 1902. 
