FORMS OF THE MALARIAL PARASITE. 477 



2. Epi- or Intra- corpuscular Bodies. These include 

 the parasites which have attacked the red corpuscles ; they 

 are at first situated on the surface of the latter but after- 

 wards penetrate their substance. They usually occur 

 singly in the red corpuscles, but sometimes two or more 

 may be present together. The youngest or smallest forms 

 appear as minute colourless specks, scarcely exceeding i /A 

 in diameter. As seen in the fresh blood, they exhibit more 

 or less active amceboid movement, showing marked varia- 

 tions in shape. The amount and character of the amce- 

 boid movement varies somewhat in different types of fever. 

 As they increase in size, pigment appears in their interior 

 as minute brownish specks, and gradually becomes more 

 abundant (Figs. 102, 103). The pigment may be scattered 

 through their substance, or concentrated at one or more 

 points, and often shows vibratory or oscillating movements. 

 This pigment is no doubt derived from the haemoglobin of 

 the red corpuscles, the parasites growing at the expense of 

 the latter. The red corpuscles thus invaded may remain 

 unaltered in appearance, may become swollen and pale, 

 or somewhat shrivelled and of darker tint. In stained 

 specimens a nucleus may be seen as a pale spot containing 

 a minute and deeply-stained nucleolus, the nucleus being 

 more distinct at some stages than at others. Sometimes, 

 namely in the quotidian and malignant fevers, the parasite 

 passes into a quiescent "ring form." The organisms in 

 this condition show a well-defined outer circular margin 

 and a central spot which is less sharply marked off, the 

 pigment being usually collected in a small clump at one 

 side (Fig. 105). These ring forms may again assume 

 amceboid movement. 



Within the red corpuscles the parasites gradually increase 

 in size till the full adult form is reached (Fig. 103). In 

 the latter stage the parasite loses its amceboid movement 

 more or less completely, has a somewhat rounded form, 

 and contains a considerable amount of pigment. Some- 

 times, for example in the quotidian form, it only occupies 

 a fraction of the red corpuscle. The adult parasites may 



