PROPHYLAXIS OF MALARIA. 
35 
noticeable between the poles of the crescent, where it forms what is 
known as the “ bib ” of the crescent. 
As the gametes of the tertian and quotidian estivo-autumnal 
plasmodia are identical in morphology, except that the quotidian 
gametes are considerably smaller than the tertian, they will not be 
described separately, and only the points of diagnostic importance 
will be touched upon in the description of these stages of devel¬ 
opment. 
In the living condition the estivo-autumnal gametes , after reach¬ 
ing the crescentic stage, are distinguished by their typically crescentic 
outline and by the fact that they appear to be extracellular, in the 
vast majority of instances. The cytoplasm appears granular in 
structure, the female form being more granular than the male, and 
the pigment is dark brown in color and either distributed throughout 
the cytoplasm or collected near or at the center of the crescent. The 
EXPLANATION OF PLATE 7. 
PLATE 7. 
Figure 1. —Phagocytosis of spomlating Plasmodium falciparum. Wright’s stain. 
X 1800. 
Figure 2 .—Plasmodium falciparum. A macrogametocyte. The female crescent 
or gamete. Wright’s stain. X 1200. 
Figure 3. —Plasmodium falciparum. A macrogametocyte. The female gamete 
or crescent. Wright’s stain. X 1500. 
Figure 4. — Plasmodium falciparum. A microgamctocytc. The male gamete or 
crescent. Wright’s stain. X 1200. 
male crescent, or gamete , is easily distinguished from the female by 
its plump kidney-like shape, the female crescent being long and 
slender. These bodies are very easily recognized in unstained speci¬ 
mens of blood and in regions where estivo-autumnal malaria is 
endemic a considerable proportion of the inhabitants will be found 
to show them in their blood. 
In stained preparations the crescents present the same staining 
reactions as do the gametes of the tertian and quartan parasites, the 
male crescent staining a pale blue while the female stains intensely. 
The following features serve to distinguish the estivo-autumnal 
microgametocytes (males) from the macrogametocytes (females) : 
1. Shape: The plump kidney shape, the macrogametocyte being 
long and slender. 
2. Staining reaction: The pale blue staining of the cytoplasm, the 
macrogametocyte staining deep blue. 
3. Chromatin: The arrangement of the nuclear chromatin in the 
form of a loose network, the chromatin of the macrogametocyte being- 
situated at the center of the crescent in a dense mass, 
