25 
PROPHYLAXIS OF MALARIA. 
• 
of being larger than normal, and paler in color, as in tertian infec¬ 
tions, is normal in size throughout the development of the quartan 
plasmodium, and slightly darker green in color than normal. 
The plasmodium slowly increases in size, and becomes less ameboid. 
The pigment increases in quantity and becomes collected at the ex¬ 
treme periphery of the organism, and is immotile. The granules of 
pigment are considerably larger than in the tertian parasite, darker 
in color, and at no stage of the growth of the organism do they col¬ 
lect in small groups throughout the cytoplasm, as is common in the 
tertian organism. As growth increases the plasmodium tends more 
and more to fill the infected red cell, and when full grown—i. e., 
at the end of 72 hours—it almost fills the cell, a narrow greenish rim 
of hemoglobin being all that is visible of the red corpuscle. At this 
stage of its growth the parasite is very distinctly outlined and is 
much more refractive than is the tertian species; the pigment is mo¬ 
tionless and collected around the periphery; the shape is spherical, 
and ameboid motion has entirely disappeared. At the end of 72 
hours sporulation occurs, the pigment being collected in the center, 
or in a star-like arrangement distributed from the center. Radial 
striations appear, dividing the organism into 8 to 12, sometimes 
16, segments or spores. The spores, or merozoites , are generally 
arranged in a perfectly symmetrical manner around the central 
clump of pigment, giving the so-called daisy or “ Margurite ” ap¬ 
pearance to the parasite at this stage of development. When sporu¬ 
lation is complete, each merozoite becomes free in the blood plasma 
and, in the human cycle, again invades a red blood corpuscle and 
repeats the process of development briefly described. 
In stained preparations, if Wright’s method be employed, the 
quartan plasmodium stains in the same general manner as does the 
tertian, the chromatin of the nucleus staining a ruby red, and the 
cytoplasm a robin’s egg blue. The youngest schizonts are the so- 
called a ring-forms ” consisting of a ring of blue-stained cytoplasm, 
with a dot or two of red chromatin somewhere near the periphery; 
while the older forms present the same general staining character¬ 
istics of the tertian plasmodium, although the cytoplasm stains more 
intensely blue and the organism is smaller at every stage of devel¬ 
opment. 
In stained preparations made during the second day of devel¬ 
opment the very characteristic u band forms ” of Plasmodium mala¬ 
rias may be observed consisting of a band of blue-stained cytoplasm 
stretching across the infected red corpuscle and inclosing a mass of 
rubv red chromatin. I have never observed these “ band forms ” 
in any other variety of malarial infection, and a diagnosis of quartan 
malarial fever is justified when such forms are observed. 
