PROPHYLAXIS OF MALARIA. 
33 
red-stained chromatin; the unstained portion of the nucleus is not 
always distinct, and the gamete is considerably larger in every stage 
of development than the schizont. The pigment is more abundant, 
while the nuclear chromatin shows no evidence of division and dis¬ 
tribution throughout the cytoplasm, being arranged in small irregu¬ 
lar masses confined to one portion of the parasite, or in fine threads 
or grains, surrounded by an unstained area, which in turn is sur¬ 
rounded by the blue cytoplasm. 
The following points are of service in differentiating tertian 
gametes from the schizonts , or forms concerned in the human life 
cycle: 1. The young gamete is never “ ringlike ” in shape, as the dot 
of nuclear chromatin is situated within the circular parasite instead 
of at some portion of the periphery. This “ bull’s-eye ” arrangement 
is characteristic, and any organism presenting it may be diagnosed 
as a gamete. 2. The gamete is larger than the corresponding stage 
in the development of the schizont. 3. The pigment in the gamete 
is larger in amount and earlier developed. 4. The chromatin is not 
distributed in the cytoplasm, but occurs in a clump surrounded by 
the cytoplasm. 5. Gametes never sporulate. 
The male gamete or microgametocyte varies in appearance when 
stained with the stage of development. The small, intracorpuscular 
gametes stain a pale blue and contain a large dot of intensely red 
chromatin situated centrally. The fully developed microgameto- 
cytes present a very poorly stained cytoplasm, the blue tinge being 
so faint in many instances as to be distinguished with difficulty, the 
cytoplasm appearing hyaline. The chromatin is large in amount, 
and in those organisms about to flagellate it is collected into several 
masses, which are arranged about the periphery of the organism. 
The pigment is large in amount and stains a greenish-blue color. 
The chromatin in the microgametocytes is always larger in amount 
than in the female gamete or macrogametocyte, and is arranged in 
the form of rather thick fibrils collected in irregular masses in the 
cytoplasm, but all of them surrounded by a single achromatic zone, 
except just prior to exflagellation. 
The female gamete or macrogametocyte of the tertian plasmodium 
stains a very intense blue, and this alone serves to distinguish it from 
the male gamete or the schizont , neither of which stain so intensely. 
The chromatin in the smallest forms appears as a single red dot 
situated near the center of the organism, while in later stages of 
development several dots or rods of this substance are present, situ¬ 
ated near the periphery and surrounded by an achromatic zone. The 
chromatin is never distributed in the cytoplasm as in the schizonts 
or in the male gamete just prior to flagellation. The pigment is 
58000°—14 
3 
