MALARIA 259 



small protoplasmic bodies appear, possessing amoeboid movement, which 

 at rest assume a ring form, finally either penetrating the red blood- 

 corpuscles, or rolling the corpuscles around themselves and absorbing 

 the haemoglobin. The duration of the vegetative period of the parasite 

 causing the malignant types is disproportionately longer than by the 

 parasites of tertiana and quartana. The fully-developed parasite is about 

 the size of a red blood-corpuscle, and in ordinary malarial fever is 

 spherical, and in malignant malaria half-moon or disc-shaped ; from these 

 forms further oval and spherical forms also originate. At the height 

 of this stage the parasites appear (probably owing to the lower tempera- 

 ture) to possess flagella, the tendency thereto varying with each group. 

 The protozoa of the malignant forms develop a distinct double-contoured 

 cuticle, while those of ordinary malarial fever possess an outer fine mem- 

 brane ; nevertheless, spore formation, excapsulation, and dissemination of 

 the young spores is analogous in both forms. In the sporulating bodies 

 of the half-moon variety, Lekowicz has counted as many as thirty spores. 

 He also distinguishes, as characteristic of the group, an extraglobular 

 incubative period of more than three days' duration ; and of the half-moon 

 or disc-shape of the fully developed individuals, four forms are determined, 

 namely 



1. Haemosporidium undecimanae. (Period of incubation, ten days.) 



2. Haemosporidium sedecimanae (fifteen days). 



3. Haemosporidium vigesimo-tertianae (twenty-two days). 



4. Haemosporidium (?) (incubative period unknown). 



The fever paroxysm coincides with the sporulation of a generation of 

 these parasites. In the malignant forms a quotidian and tertian type is 

 frequently observed, because many generations of parasites, differing in 

 age from twenty-four to twenty-eight hours, are present. The presence 

 of the tertian type in these cases is explained by a severe attack inter- 

 fering with the formation of the active living spores of the immediately 

 following twenty-four hours' younger generation, without influencing the 

 forty-eight hours' younger generation, in which encapsulation has not yet 

 taken place. The half-moon forms are by no means inaccessible to the 

 action of quinine as heretofore accepted. Their resistance is only so 

 altered that the quinine impairs the vitality of, or destroys, the complete 

 half-moon forms capable of forming spores of several generations of 

 simultaneous existing parasites, but it does not prevent previously existing 

 young and half-grown sporidia in the internal organs developing into 

 half-moon forms. After treatment with quinine the half-moon forms are 

 still present one to two weeks later in the blood. 



METHOD OF PREPARING DRY SPECIMENS. 



1. The cover-glass with the drop of blood in its centre is drawn 

 quickly across another cover-glass, and both are azr-dried, protected from 

 dust. 



