PLASMODIUM MALARIA. 627 



There is still much uncertainty with regard to the 

 classification of the parasites. Many authors place them 

 among the sporozoa in the order of the hoemosporidia of 

 Danilewsky; others place them in the aarcodinia, and 

 speak of them as hcemamcebce. Until the matter is settled, 

 however, they may be considered to belong to the gen- 

 eral order of protozoa and to that group of organisms 

 known as hcematozoa. Parasites of the red blood-cor- 

 puscles have been met with abundantly in the blood of 

 fish, turtles, and many species of birds. 



The relation of the different forms of the malarial 

 parasite to each other and to the varieties of the disease 

 are still under discussion. Galgi, Marchiafava and 

 other Italian observers hold that they are distinct 

 varieties, not interchangeable, though closely allied 

 biologically. Laveran, on the other hand, contends for 

 the unity of the forms, which he regards as modifica- 

 tions of one polymorphic parasite. But with the 

 present imperfect knowledge of the full life-history of 

 the parasite the question cannot be considered as settled. 



The following varieties are associated with the differ- 

 ent forms of malarial fever : 



I. Parasite of the Simple Intermittent Fever, (a) TER- 

 TIAN PARASITE (see Plate II.). If the blood of a 

 patient be examined during or shortly after the chill 

 in tertian fever, inside the red blood-corpuscles, or less 

 often free in the plasma, will be seen small, pale, hya- 

 line amoebae which undergo rapid changes in shape, 

 often assuming the form of a star or of a cross. There 

 may be no pigment visible, and to these hyaline bodies 

 Marchiafava and Celli gave the name plasmodia. In a 

 few examples scattered pigment granules may be seen 

 in the amcebse, usually placed near the periphery. In 



