vm CONQUEST OF DISEASE 225 



investigators that these creatures are the sole agents 

 of inoculation into man of the germs of malaria, 

 yellow fever, sleeping sickness, plague, East-coast fever, 

 Kala-azar, typhus fever, recurrent fever and other 

 maladies which have brought suffering and death to 

 millions of people. In most cases they are not merely 

 mechanical bearers of disease germs from one victim to 

 another, for if that were so the problem of discovering 

 the part they play would be relatively simple. Usually 

 their bodies are breeding-places of microscopic organisms 

 which they suck from the blood of one victim beast or 

 man and these parasites, after undergoing profound 

 transformations within their hosts, are afterwards 

 injected into other victims. Insects have thus been 

 shown to be intimately related to the life of man ; and 

 a branch of study which was formerly considered to be 

 of purely zoological interest has proved to be closely 

 connected with practical problems of European colonisa- 

 tion in tropical regions. 



If it is better to save life than to destroy it, then laud 

 and honour should be given to those patient scientific 

 investigators whose studies have shown how to lessen 

 human suffering and prevent the spread of fatal diseases. 

 Before a disease can be prevented it must be under- 

 stood ; there must be a knowledge of its nature and 

 mode of transmission if a sure remedy is to be found, 

 and that knowledge is obtained by the man of science, 

 whose work meets with little encouragement either 

 officially or publicly, and is usually without reward. 



No better examples could be found of the benefits 

 of such work to the human race than are afforded by 

 the studies of tropical and other diseases carried on in 

 recent years. Perhaps the most important of these 

 diseases is malarial fever, which causes the death of 



G.D. P 



