EDITOR'S INTRODUCTION xv 



To deal with these problems, a cry is going up for economic 

 entomologists, mycologists, soil biologists, and the rest. Ad hoc 

 training in these and similar subjects is being given at various 

 centres, and special laboratories are being erected for research 

 in the separate branches. Valuable results are being achieved : 

 but the general biologist is tempted to ask v^hether in the quest 

 for specific knowledge and specific remedies it is not being 

 forgotten that behind all the detail there is to be sought a body 

 of general principle, and that all these branches of study are 

 in reality all no more and no less than Applied Ecology. The 

 situation has many points of resemblance to that which ob- 

 tained in medicine in the last half of the nineteenth century. 

 Then, under the magic of the germ- theory and its spectacular 

 triumphs, medical research on disease was largely concentrated 

 upon the discovery of specific " germs " and their eradication. 

 But as work progressed, the limitations of the mode of attack 

 were seen. Disease was envisaged more and more as a 

 phenomenon of general biology, into whose causation the 

 constitution and physiology of the patient and the effects 

 of the environment entered as importantly as did the specific 

 parasites. 



So it will be with the control of wild life in the interest 

 of man's food-supply and prosperity. The discovery of the 

 tubercle bacillus has not led to the eradication of tuberculosis : 

 indeed it looks much more Hkely that this will be effected 

 through hygienic reform than through bacteriological know- 

 ledge. In precisely the same way it may often be found 

 that an insect pest is damaging a crop ; yet that the only 

 satisfactory way of growing a better crop is not to attempt 

 the direct eradication of the insect, but to adopt improved 

 methods of agriculture, or to breed resistant strains of the crop 

 plant. In other words, a particular pest may be a symptom 

 rather than a cause ; and consequently over-specialisation in 

 special branches of applied biology may give a false optimism, 

 and lead to waste of time and money through directing atten- 

 tion to the wrong point of attack. 



The tropical entomologist or mycologist or weed- controller 

 will only be fulfilling his functions properly if he is first and 



