288 
Trt/paiiosouiiasis 
other regions. It is, moreover, by no means certain that domesticated 
animals would not have to be likewise destroyed, for they, too, may act 
as reservoirs. In view of the wide range of pathogenicity possessed by 
T. gamhiense there is always the possibility of animals serving as 
reservoirs which it will be practically impossible to exterminate. On 
the other hand there is hope that by reducing the number of reservoirs 
and Glossinas the chain of parasitism may be broken, as it may be 
in malaria by mosquito reduction. Judging from the observations on 
Glossinas captured in a wild state, but a very small number of these 
are infective; the percentage of such flies may be sufficiently reduced 
to greatly lessen the danger of infection through their agency. In the 
case of G. palpalis, which has a relatively stationary habitat in proximity 
to water, we have a comparatively easy problem to deal with as com¬ 
pared to G. morsitans. The latter fly, which conveys T. rhodesiense, is 
migratory, it ranges widely, and it resists dryness such as G. palpalis 
cannot withstand, and therefore to attack its habitats successfully appears 
practically impossible. A measure of protection will no doubt be 
afforded by putting the land, in the vicinity of human habitations, 
under suitable cultivation. We know that the main roads of travel 
are the most dangerous and that the old native measure in respect to 
Nagana of avoiding the fly belts by day is safely to be relied upon. 
It is cle?ir that the study of the biology of the carriers of trypano¬ 
somes has become one of great practical importance, and that we are 
gradually accumulating data upon which we can proceed in a rational 
manner to combat trypanosomiasis. 
Note : Those desiring to consult the literature on Trypanosomiasis are referred to the 
Sleeping Sickness Bulletin. The Lecturer has purposely refrained from giving references 
so as not to burden the text. 
