DOUBLE INFECTION OR QUOTIDIAN IN TERMITTENT FEVER.—In the blood will be found two groups of tertian parasites in different stages of development and reaching maturity or the stage of segmen tation upon alternate days. In conse quence, quotidian or daily paroxysms occur, which do not differ in their clinical manifestations from the paroxysms in cident to single tertian infection. Inas much as one group may be larger than the other at the time of infection, it is not uncommon for the paroxysms to be tertian in type until the smaller group has attained sufficient size to cause a paroxysm. Further, as one group may, throughout, be more numerous than the other, it is not uncommon for the parox ysms produced by this group to be more severe than those produced by the other. It is usual, also, for one group of para sites to undergo segmentation at a differ ent hour from the other group, resulting, of course, in a constant difference in the hour of onset of the paroxysms.
Infection with multiple groups of parasites is so rare as to be of no clin ical importance. Such an occurrence, of
course, would give rise to a very irregular type of fever. (See temperature-chart.) Quartan Fever.—SINGLE INFECTION. —The paroxysm in quartan fever is simi lar in every respect to that occurring in tertian fever. Examination of the blood shows the presence of a single group of quartan parasites the members of which are about in the same stage of evolution • 21 • . - t t tut. The time required r t on of the cycle of (level . . , t •-tNtitty-two hours; sor t.., ite;dent as they are • . 111.111011 1.11 I 11 parasites, Nt.r% • -urth d.tv.. an intermission ful cx'sting between. The \\ tImractcrized by the threeftvir. and sweating, and .r. f an avt.rage duration of about ten r Z1 t 11 They occur with greattv and show but little tendency cessive days followed by a day of inter mission, are in every respect similar to those occurring- in single infection.