GAME ANIMALS TO DISEASE IN AFRICA 23 
life in the infected areas, and even then there appears to be no 
absolute guarantee that success will follow. Such a process 
may be described as reductio ad absurdum in more senses 
than one, for it is open to the gravest doubt whether it is pos- 
sible to exterminate all vertebrate life, even in a limited area, 
and it is certainly impossible on a practical scale. 
In the New Cameroons Professor Schillings thought that 
to get rid of all the animals, both wild and domestic, which 
might act as a reservoir of sleeping sickness was impossible, 
and that every endeavour should be made to advance chemo- 
therapeutic discoveries (‘ Sleeping Sickness Bulletin,’ No. 84, 
p. 89). 
Professor Dr. M. Beck is of opinion that immunity in 
larger animals and cure in others will eventually be obtained 
(‘ Sleeping Sickness Bulletin,’ No. 21, p. 864). 
It appears therefore that before any extensive measures 
of extermination are undertaken in any part of Africa it will 
be the wiser plan, if not absolutely essential, first to ascertain 
definitely all the animals (taking into consideration not game 
animals alone) which are acting as reservoirs for the virus of 
any trypanosomiasis. 
This is an undertaking of great difficulty, but it is certainly 
more practical and less costly and destructive than a policy 
of extermination, and will prevent what might possibly prove 
to be the useless extermination of countless numbers of beauti- 
ful game animals. For it would certainly be a useless pro- 
ceeding if it was afterwards found that many other animals 
were acting as reservoirs of infection. 
In view of these facts I wish to draw particular attention 
to a subject which has not received from the general public 
the attention that it merits, and that is the question of im- 
munity and the possibility of producing it or hastening it 
artificially. The task of exterminating all animal life in the 
infected areas, or the insects which transmit the diseases, is 
such a gigantic one that it appears almost impossible, and 
the prospects of success by producing an immunity appear 
to many more hopeful. 
This applies also to the piroplasmoses. Some important 
information will be found under the heading 4 Studies in 
