DOFLII.1; INFECTION', OR DOUBLE QUAR TAN FEVER. This occurs when two of quartan parasites exist in the Hod d' the same time, and attain the zi ye of --...-rat,ntation upon successive days. In this manner one day of inter7 then IThon examination r f thp 11(c.d the existence of these two ,-rour, can be readily observed. The F.aroxy,,rn= which occur upon two sue two groups of tertian parasites. The par oxysms are clinically similar to those already described as occurring in the single and double infections.
Estivo-autumnal Fever. The most important particular in which the fevers of this group differ from the regularly intermittent fevers is the marked tend ency which they show to become per nicious. The reg.ularly - intermittent fevers when untreated tend to spontane ous recovery, and rarely, except in the I most intense infections, develop grave, pernicious symptoms. The mstivo-au tumnal infections, however,of course with many exceptions in which the tend ency to spontaneous recovery is seen, pass on to a fatal termination with the development of pernicious symptoms mhen left to themselves.
This group of fevers, of course, de pends upon infection with the Festivo autumnal parasite and clinically is to be observed in ntany forms. Two principal
forms, however, may be recognized: quotidian intermittent fever and wslivo autumnal tertian. fever, or maligna-nt ter tian fever. Owing to the marked irregu larity which is a characteristic of almost all mstivo-auturnnal fevers, it is not al ways possible to sharply classify the vari ,' ous cases. The chief reasons for the I tendency toward irregularity in this in ' , fection are: 1. The cycle of development of the parasites is not so nearly simul , taneons in the different members of the 1 group as it is in the regularly-intermit tent fevers, and as a result sporulation is not completed in the short space of a few hours, but continues to occur for twenty-four to thirty-six hours. The . ' consequence is the prolongation of the ' paroxysm. 2. The different parasites do not all take the same length of time to ' attain maturity, as is the ease in the regularly-intermittent fevers, but show a marked tendency toward the hastening of sporulation, with resulting anticipa tion of the succeeding paroxysm. 3. Sev eral generations, though seldom niore than two, and mixed infections are of fre quent occurrence. (Mannaberg.)