630 APPENDIX. 
in so doing usually form distinct rays. Then, as in 
the tertian form, the organism begins to segment ; a 
marginal indentation is first seen, with lines of radia- 
tion, and a beautiful rosette is formed, which segments 
into from six to ten, occasionally twelve, small, spher- 
ical or ovoid bodies. The character of the pigment, 
the smaller size of the organism, and the development 
are differences which separate the quartan from the 
tertian variety. 
In the quartan malarial fever the blood may show 
two or more groups of parasites. There may be two 
groups which reach maturity on successive days, with 
one day interval—double quartan fever; or there may 
be three groups of organisms maturing on successive 
days, causing daily paroxysms—triple quartan fever. 
JJ. The Aistivo-autumnal Parasite (see Plate II.). 
In the more irregular and as a rule pernicious types 
of malarial infection which are met with in the autumn 
months a third variety of organism may be recognized, 
which has been specially studied by the Italian obser- 
vers. The youngest forms of this parasite are small 
hyaline bodies about one-sixth the diameter of the red 
cell. At first they are quiescent, but later develop 
active amceboid movement. They are at this stage 
not unlike those of the tertian varieties; but the hya- 
line body is more signet ring-like, more highly refrac- 
tile, and the central part often looks shaded, as if a 
more solid body were enclosed within a vacuole. As 
this form increases the amceboid movements are well 
seen. The pigment is in small amount, at first in the 
form of one or two very dark granules at the margin 
of the amcbe, and the pigment never becomes so 
abundant as in the tertian or quartan forms. The 
