(2) _Those in which the succession of cold, hot and sweating stages is lacking._ There is not the frank well-defined chill of the former group, so that the term dumb chill is frequently applied. With the possible exception of the first paroxysm the temperature tends to remain well above normal giving a continuous, or at any rate a remittent type of fever, instead of the intermittent temperature curve of the benign infections. The designation _remittent fever_, is often applied to such fevers. Clinically there is a resemblance to typhoid fever. Such malarial fevers are caused by the small hair-like ring parasite with its crescent sexual forms. There are many designations for this type of malarial fever of which the best recognized are: _malignant tertian_, _subtertian_, _aestivo-autumnal_ and _tropical_. It is preëminently the malarial fever of the tropics and, from its appearing in temperate climates chiefly in the late summer and through the autumn months, received from the Italians the designation aestivo-autumnal. Such fevers were called subintrant by Torti because the succeeding paroxysm set in before the completion of the long-continued preceding one. This type of fever was greatly dreaded. The designation _malignant tertian_ is to be preferred as indicating the greater seriousness of this type of malaria. INCUBATION PERIOD Depending in great part on the number of sporozoites introduced by one or more infecting anophelines at the time of biting we have with quartan fever (8-12 merozoites) a period of incubation of approximately three weeks, for benign tertian (16-24 merozoites) two weeks and for malignant tertian (32 merozoites in culture) eight to twelve days. These periods however may be much longer. PRODROMATA There may be prodromata of the nature of malaise, vague muscular pains, headache and anorexia, possibly showing a periodicity in their appearance or intensity. It is only when a sufficient number of parasites sporulate simultaneously and pour out into the circulation sufficient toxic material to cause a well-marked paroxysm that such occurs—with less poison we may only have vague suggestions of an attack of ague. In a large proportion of cases there are no prodromata, they begin with a sudden onset. Malarial paroxysms show a preference for the forenoon or at any rate tend to occur in the early afternoon, rather than in the evening. MIXED AND MULTIPLE INFECTIONS