PROPHYLAXIS OF MALARIA. 
37 
Stained preparations. — 1 . Medium size of pigmented organisms. 
2. No increase in the size of the infected red blood corpuscle. 3. Ab¬ 
sence of Schuffner’s dots (eosinophilic granules) in cytoplasm of 
infected cell. 4. Number of spores {merozoites) , 6 to 12. 5. Pres¬ 
ence of all stages in the peripheral blood. 6. Presence of the “band 
forms.” 
C. Plasmodium falciparum (tertian estivo-autumnal plasmodium). 
Unstained preparations. —1. Small size, even when fully devel¬ 
oped. 2. No enlargement of infected corpuscle, which is smaller 
than normal. 3. Small amount of fine brownish pigment. 4. Num¬ 
ber of merozoites . 10 to 10. 5. Only ring forms and young pigmented 
forms present in the peripheral blood, and crescents. 0. Crescentic 
shape of the gametes. 
Stained preparations. — 1. Small size, even the sporulating forms 
only partly filling the infected cell. 2. No enlargement of the in¬ 
fected corpuscle. 3. Presence of Maurer’s dots or basophilic gran¬ 
ules in the cytoplasm of the infected cell. 4. Number of merozoites , 
10 to 16, as a rule, very small and arranged irregularly. 5. Only 
“ ring-forms ” and young pigmented forms occur in the peripheral 
blood, as a rule, together with crescents after the infection has 
persisted for several days. (>. Crescentic shape of the gametes. 
D. Plasmodium falciparum quotidianum (quotidian estivo-autum¬ 
nal plasmodium).—The quotidian estivo-autumnal plasmodium dif¬ 
fers from the tertian form, in both fresh and stained preparations, 
by its smaller size at every stage of development, while the mero¬ 
zoites number from 6 to 18, the average being from 12 to 14. The 
organism contains less pigment, which is collected into one or two 
almost black masses, and the sporulating forms seldom fill more than 
one-third of the infected red blood corpuscles. The hyaline “ ring- 
forms ” are very minute, resembling in this respect the piroplasma. 
Objects which mag be mistaken for plasmodia in stained, and un¬ 
stained specimens of blood. —There is no one thing more essential to 
success in the recognition of the malaria plasmodia than a practical 
knowledge of the miscroscopical appearance of both fresh and stained 
specimens of normal and pathological blood. It is surprising how 
often some artefact or other object is mistaken for a malaria plas- 
modium by medical men from whom such a mistake would not be 
expected, and it is always due to ignorance of the morphology of 
the blood, an ignorance that can not be excused, for the blood “we 
have always with us" and anyone may be become perfectly familiar 
with its morphology who capes to take the time to make a few prep¬ 
arations and to study them. Mistakes are more apt to occur in ex¬ 
amining fresh blood but a little care and practice will enable one 
to avoid them and with the excellent Wright stain it is inexcusable 
to mistake any object for a plasmodium in stained preparations. 
