78 
SPOLIA ZEYLANICA. 
OBSERVATIONS ON THE HJEMATOZOA OF VERTEBRATES 
IN CEYLON. 
(d. Preliminary Note.') 
By 
ALDO CASTELLANI, M.D., 
Director of the Bacteriological 
Institute , Colombo. 
and 
Arthur Willey, F.R.S., 
Director of the Colombo Museum. 
With Plate. 
Introduction. 
T HE investigations into the parasitology of the blood have 
yielded such great results within the last ten years, import¬ 
ant alike from the point of view of practical medicine and from 
that of pure biology, that no apology is needed for the present 
contribution to the very extensive literature of the subject, 
especially because no systematic work of the kind has yet pro¬ 
ceeded from the Island of Ceylon. 
The microscopic organisms (apart from bacteria) which more or 
less frequently infest the blood of certain vertebrates belong to 
two different branches of the animal kingdom, namely, the 
nemathelminthes (nematoda) or thread-worms and the protozoa 
or unicellular animals. 
The protozoan haematozoa belong to t wo distinct classes, firstly 
the sporozoa, which are predominantly endoglobular, living at least 
throughout the first period of their growth within the substance of 
the individual blood-corpuscles from which they or their progeny 
can emerge under certain circumstances and at certain periods ; 
secondly, the flagellata which swim about freely in the plasma of 
the blood. 
The parasitic infection of the blood due to the presence therein 
of minute thread-worms is called filariasis; that due to the 
flagellata is called trypanosomosis ; and the sporozoan infection 
is termed haemosporidiosis. 
The dreaded human malaria comprises the particular forms in 
which, haemosporidiosis manifests itself in man. Another form of 
