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recurred in from five to ten days, and further doses of atoxyl caused 
signs of poisoning. 
‘ According to the observations of the Liverpool workers, it is 
surmised that mercury in the form of corrosive sublimate will prevent 
the recurrence, when once the trypanosomes have disappeared from 
the general blood stream. It has been shown that cattle will tolerate 
the administration of one gramme of this salt given by the mouth, in 
I in 500 solution, on three successive days. It was necessary for me 
to leave Broken Hill before the combination of these two drugs could 
be tried in these doses, but the course of the experiments indicate 
that the greater the amount of mercury given, the longer the period 
of freedom from trypanosomes in the blood, and it may be shown 
that even more mercury than this could be tolerated by cattle, and 
would be necessary to bring about absolute absence of the germs 
and complete cure. 
‘(5) No exact experiments with regard to the mode of 
transmission of this disease were made. Two healthy cattle were 
walked through a narrow fly belt, and three tsetse flies (Glossina 
niorsitans) were observed to bite. Fifteen days later both showed 
T. vivax in their blood and on the eighteenth day T. dimorphon. 
This is about the normal incubative period, and I have little doubt 
but that they derived the double infection at the time when the 
tsetse flies were seen to feed. 
‘ The investigations made into one outbreak, and all circumstances 
relating thereto, throw a very strong suspicion upon two species of 
biting flies as transmitters of this disease. These species belong to 
the genera Stomoxys (stinging house-fly) and Lyperosia, a very 
diminutive fly, similar in shape to the ordinary house fly. These two 
genera frequent farmyards, stables, and habitations, and breed in 
manure pits and dung. The former is incriminated in the natural 
spread of “ fly disease ” in Central South America and the Philippine 
Islands. 
‘ Another genus of biting fly which has become excessively 
prevalent as I leave here is the Tabanus, or “gad fly.” This fly is 
responsible for spreading “ fly disease ” in Algeria and India. 
‘ (6) My brief work and observations here have shown how urgent 
is the need for more research into this disease which is impeding the 
development of the country around rail head, and how imperative it 
