OBSERVATIONS ON HAIMATOZOA IN CEYLON. 383 
Observations on Hzematozoa in Ceylon. 
By 
Aldo Castellani, M.D., 
Director of the Bacteriological Institute, Colombo, 
and 
Arthur Willey, F.R.S., 
Director of the Colombo Museum. 
With Plate 24. 
Tux observations recorded in this paper were made primarily 
with the object of ascertaining the distribution, frequency, and 
forms of infection of the parasites of the blood of vertebrates 
in Ceylon. 
Since the publication of our preliminary note (‘ Spolia 
Zeylanica,’ vol. ii, part 6, August, 1904, pp. 78-92) a few 
more cases have come under our notice, and as there is no 
immediate prospect of amplifying our investigations owing 
to the pressure of other duties, we deem it advisable to pub- 
lish our results in full without further delay. The discoveries 
of Ross, Grassi, Schaudinn, and others, have rendered it clear 
that researches on blood parasites must be undertaken with 
a single aim, and with undivided attention, in order that 
they may be cyclically complete. 
It seems that the experimental difficulties which beset the 
investigation of the life-cycle of the hemogregarines and 
trypanosomes of cold-blooded animals are great; and the 
ignorance as to the means of transmission of these parasites, 
and with regard to the order of succession of their different 
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