256 THE PROTOZOA 



VARIOUS TYPES OF MALARIAL PARASITES. 



(1.) The Quartan Parasite. The cause of quartan malaria has an 

 incubation period of seventy-two hours ; they are not strongly motile. 

 At first the parasite occupies J or J of the blood-cell, and large quanti- 

 ties of granular pigment are present. Losing its motility it increases 

 in size, until it appears to fill the whole blood-cell. It then forms 

 spores, arranged like the ray-flowers in a daisy-marguerite form, having 

 eight to twelve round spores, the whole period of development occupy- 

 ing about three or four hours. The segmentation takes place both 

 before and during the febrile stage ; and about three hours before the 

 outbreak of the rigors, the first mature spores are visible in the blood. 



The red blood-corpuscles affected with the quartan parasite do not 

 alter their size. The parasites sometimes sporulate before completely 

 filling the blood-cell, when they only form four to five spores. Cilia 

 are only observed in young forms. If many generations of the quartan 

 parasite are present in the blood, then it causes quartan duplex or 

 triplex, or an irregular type of fever. 



(2.) The Tertian Parasite. The cause of the tertiana form of malaria 

 develops in forty-eight hours ; the young form resembles the quartan 

 parasite. It is strongly motile, possessing pseudopodia, contains pig- 

 ment, enlarges the red blood-corpuscles containing them, and sporulates 

 in the form of a rosette, or like a sunflower containing fifteen to twenty 

 spores which are smaller than those of the quartan parasite, the nucleus 

 only being observed with difficulty. The free spores infect fresh blood- 

 corpuscles in a short time, completing the same above-mentioned cycle of 

 development. All the tertian parasites do not sporulate, a large number 

 remaining sterile. These sterile parasites are as large or larger than 

 the sporulating forms, and the pigment remains motile. (Laveran con- 

 siders this a degenerative process.) They can be observed in the blood 

 hours after the attack, and also during the fever-free days. The 

 process of sporulation is coincident with the fever paroxysms in the 

 tertiana form. Golgi found that three hours before the rigors com- 

 menced, the temperature had already begun to rise, and that the first 

 spores were already apparent in the blood, but they were most plentiful 

 during the rigors. The full - grown tertian parasite often possesses 

 flagella. (Kruse considers this condition likewise a degeneration.) The 

 tertian parasites cause typical tertiana ; two generations of the same can 

 produce a false quotidiana. Tertiana duplex generates several generations 

 separated about twenty-four hours from each other, causing irregular 

 fever. 



(3.) The Quotidian Parasite. The commencement of the cycle of 

 development of this parasite, which requires twenty-four hours for its 

 completion, is similar to that of the previous forms. The young form 



