132 
Haemoflagellates, etc. 
Woodcock has compiled a very complete list of all the known hosts 
of the haemoflagellates and allied forms; this list ought to be of great 
use to subsequent observers. The flagellates of insects and leeches are 
confused with trypanosomes, and we note that the Crithidia we described 
from Gerris fossarum is wrongly called a Herpetomonas. A fairly com¬ 
plete list of references to the literature concludes the article ; many recent 
important papers are however entirely omitted. 
After having carefully read Woodcock’s article on the Haemoflagel¬ 
lates we regret we are unable to recommend it to students of Tropical 
Medicine and Protozoology as it is already out of date and quite inade¬ 
quate for their requirements ; it is too full of hypotheses and dogmatic 
assertions, which are based, in many instances, on ei’roneous observations. 
It is quite evident Woodcock has had very little practical experience 
with the majority of the parasites he describes, his facts having been 
collected from various sources and containing nothing original. The 
result is that he is not in a position to form a sound judgment on the 
mass of observations he has attempted to describe. Under the circum¬ 
stances we consider Woodcock would have done much better had he con¬ 
tented himself with a detailed description of the various Haemoflagellates 
and the numerous insect forms, adding to this some original drawings. 
Before concluding our review, we wish to indicate what we consider 
should be the future lines of research on these important parasites. It 
is now conclusively proved that certain trypanosomes, T. gambiense, T. 
brucei and T. lewisi are transmitted mechanically by insects, for instance 
T. gambiense by G. palpalis, T. brucei by G. morsitans, G. pallidipes and 
G. palpalis. 
Excluding the natural flagellates of these insects, there is no evidence 
to show that these trypanosomes undergo a true developmental cycle in 
the alimentary tracts of their insect transmitters. Where then do these 
trypanosomes pass the important stages of their life histories ? Salvin- 
Moore and Breinl’s recent observations suggest that some of these blood 
flagellates manifest a cyclical metamorphosis, which corresponds closely 
to an alternate absence and presence of the parasites in the blood of their 
vertebrate hosts. Latent bodies consisting of a nucleus and a vesicle 
surrounded by a delicate covering of cytoplasm are formed when the 
parasites are at their minimum in the peripheral blood. These non- 
flagellate stages are found in the spleen and bone-marrow, and later give 
rise to flagellates. During the formation of these latent bodies there is 
an interaction between the blepliaroplast and the nucleus; does this 
represent a sexual phase ? In the light of our knowledge that a number 
