PARASITE OF PERNICIOUS MALARIA 191 
of fresh blood, unstained, placed upon a slide and under cover-glass. It is the 
method least employed because it requires greater technical skill; it permits, 
however, all the details to be seen, as Schaudinn has shown. Among other 
notable achievements he succeeded with this method in following clearly the 
penetration of the sporozoit into the blood-cell. The second method consists 
in staining the blood which has been spread in a very thin layer upon a micro- 
scope-slide. There are various methods of staining which all have as a basis 
more or less the same color substances. That most in actual use, because it is 
the simplest and the one which enables all the details of the parasite to be dis- 
tinguished, is the process of Giemsa. 
Plasmodium malarie (the organism of quartan malaria).—When one ex- 
amines with the microscope a slide with live parasites of quartan fever one sees 
that their movements are much weaker than those of Plasmodium vivar. The 
black pigment-granules appear early; the parasitized red blood-cell shrinks a 
little, and in stained preparations this can be seen readily. The quartan parasite 
sometimes also produces a heavier coloration ; however it does not possess granu- 
lations like those of Schiiffner (seen in stained preparations as small red dots) 
in Plasmodium vivax, or of Maurer (a very few dots) in P. falciparum. Schi- 
zogony takes place only in the peripheral circulation. The parasite divides into 
from 8 to 14 merozoits arranged with great regularity, hence this phase is some- 
times called the “rosette,” “daisy,” or “marguerite” form. The evolution 
takes longer than in any other plasmodium, 72 hours being consumed from one 
schizogony to the next. There is a characteristic appearance which this parasite 
assumes during growth, that of a more or less broad band across the corpuscle - 
which is by many called the aquatorial band. The gametes are round, not only 
when inside of the corpuscle, but also when free in the blood-plasm. 
Plasmodium falciparum.—The disease caused by this parasite goes under 
several names: quotidian, malignant tertian, atypical, irregular, estivo-autum- 
nal, pernicious, or tropical fever. The Germans follow Koch and use the term 
“ tropical fever ” but this expression is not in accord with the geographic dis- 
tribution of the parasite. The differentiation of this parasite is based more on 
clinical data than on the structure and biology of the organism. When alive the 
schizont is very active. Schizogony takes place in less regular periods than in 
the other parasites, fluctuating between 24 and 48 hours. Doflein states that 
there may be a prolonged period of 72 hours. Also the number of merozoits is 
variable and may range from 4 to 30, although commonly between 6 and 14. 
The division always occurs in the internal organs ; in acute cases it can, however, 
also be found in the periphery. In this parasite there is commonly formed a pre- 
cocious division in the young forms, a fact which explains the rapid progress 
which pernicious attacks make. Besides the habitual cycle, then, the parasite 
can subdivide before it has completed it. It is quite common to find blood-cells 
containing more than two schizonts ; there have already been found as many as 
6 or 7 in a single corpuscle. A peculiarity of this parasite is its retreat to the 
internal organs after 30-36 hours; after having divided the parasites reappear 
in the periphery, generally two or three hours after this process. To this phe- 
