258 THE PROTOZOA 



in forty-eight hours, being larger, and at the time of sporulation occupies 

 one-half to two-thirds of the blood-corpuscle; no pigment is formed for 

 over twenty-four hours, and when it is formed the motility of the 

 parasites is not impaired. Circular forms, and later on half-moon forms, 

 also develop. It has usually 8 to 15 spores. The infected blood- 

 corpuscles become copper-coloured, shrivel easily, but never hypertrophy. 

 These peculiarities distinguish this parasite from Golgi's ordinary tertian 

 parasite, which, moreover, in all described stages is larger, richer in 

 pigment, and forms more spores, 15 to 20. The malignant tertian 

 parasite generates a severe tertian form of fever, the chart showing 

 peculiar curves, with very short fever-free intervals, often only of a few 

 hours' duration, and with regular pseudo-crises ending in continued or 

 irregular fever. The quotidian parasite also exhibits malignant 

 characters. 



Mixed Infection. In many cases of intermittent fever various forms of 

 the above-mentioned parasites are present at the same time in the 

 blood. Quotidian parasites frequently occur beside non-pigmented, and 

 the quartan sometimes beside the tertian parasite. Golgi found in one 

 case three generations of the quartan parasite and two of the tertian 

 parasite. In the fever curve of the chart we may find the different 

 parasites showing their effects simultaneously, or an irregular type of 

 fever may be manifested. It also happens that during the course of the 

 fever only one form of parasite causes the changes, the others apparently 

 having no influence. 



According to Lekowicz's investigations of malignant and ordinary 

 (tertiana and quartana) malarial fever, the parasites of both groups 

 develop in a similar manner, but are differentiated as follows : (a) Length 

 of the period of incubation ; (6) the size and form of the parasite found 

 in the same stage of development ; (c) the presence of melanin ; (d) the 

 presence of flagella and the number of spores present. However, the 

 greatest differentiation is that the parasites of ordinary malaria develop 

 within the cell (endoglobular), while those of the malignant forms are 

 developed without the cell (extraglobular). The former grows within the 

 red blood-corpuscles, the latter rolling the red corpuscles around them- 

 selves like a caterpillar does a leaf, whereby a part of their surface 

 remains free, enabling them to attach themselves to the wall of the blood- 

 vessels. When the parasite is separated from the blood-corpuscles by 

 pressure of the cover-glass in cases of ordinary malaria forms, the wall 

 of the corpuscle is ruptured, and the pigment escapes outwards, the 

 remainder of the corpuscle being immediately decolorized. In cases of 

 malignant malaria the wall and the pigment of the blood-corpuscle 

 remain intact, and the parasite is not in the interior of the cell, but lies 

 in a small cavity formed by the rolling process. The growth of the 

 parasites in both instances is identical. At the end of the febrile stage 



