INFECTION IN INTERMEDIATE HOST: FALCIPARUM 
197 
it is less than 99° F at the onset of the 
paroxysm; a normal temperature is not 
unusual. Aching is usually more severe in 
P. falciparum infections and if a rigor is 
present it is ordinarily less marked than in 
vivax or quartan malaria. Vomiting occurs 
most frequently at the end of the cold stage 
or early in the febrile phase. Pain over the 
epigastric or splenic areas is commonly 
severe. The long duration of fever is an 
outstanding feature of P. falciparum 
paroxysms. 
Periodic elevation of the temperature is, 
by definition, the only constant character¬ 
istic of the malarial paroxysm. Rigors are 
not as frequent constituents of the falci¬ 
parum paroxysm as of those due to P. vivax. 
Marchiafava and Bignami (1901) expressed 
the opinion that the fact that sporulation in 
estivo-autumnal malaria occurred “in the 
vessels of the internal organs under rela¬ 
tively stable conditions and the parasitic 
forms which finally produce the fever are 
not circulating” had a bearing on the fre¬ 
quent absence of the chill. In our experi- 
enpe with several strains of P. falciparum 
which we have utilized (ranging in point of 
origin from the southern United States, 
Cuba, Mexico and Central America), the 
rigor.has been an unusual predecessor of the 
febrile stage in the American negro, in 
whom we recognize some degree of racial 
immunity. In an unselected group of 20 
such patients, 136 paroxysms were observed 
and only one of these was initiated by a 
rigor. These patients, however, commonly 
complain of “dumb chills” (chilly or cold 
sensations). In white patients, on the other 
hand, the picture has been somewhat dif¬ 
ferent. Here a much larger proportion of 
the paroxyms are accompanied by rigors; 
for example, of 231. paroxysms experienced 
by 10 persons, 69, or practically 30 per cent, 
commenced with a rigor (even this inci¬ 
dence of rigors is well below the usual find¬ 
ing in susceptible white patients with P. 
vivax infections). 
Some of the early Italian writers evolved 
elaborate classifications of the pyrexial reac¬ 
tions of individuals infected with P. falci¬ 
parum. This would seem neither necessary 
Fig. 1. No. 258 (P. falciparum) : Onset with re¬ 
mittent-quotidian type of fever which becomes 
intermittent. Breaking up of lesser cycle into 
several peaks on 8th and 10th days, producing 
remittency again. 
nor desirable in considering our observa¬ 
tions in this country. Mannaberg (1905), 
aiming toward simplification of nomencla¬ 
ture, rightly stated that such differentiation 
was lacking in practical value. The same 
author noted that “the form of the fever 
and the severity of the infection do not cor¬ 
respond. ’ ’ 
Fig. 2. No. 1111 and 1150 (P. falciparum ) : Both 
experienced brief tertian courses. In both instances 
a second cycle showed a tendency to develop but 
did not reach pyretogenic levels. 
