THE KINGDOM OF MAN 231 



it is easy to spoil a countryside unless there are five 

 seedlings planted for every good tree cut down ; but 

 this is the mere alphabet of science. 



The secret of domesticating animals seems to have 

 been lost, or perhaps the number of domesticable animals 

 is very small ; but there are surely enormous possibilities 

 of new cultivated plants. 



§ 4. Control of Disease 



The great steps that Man has taken in the control 

 of things have been very largely due to scientific genius. 

 " If necessity is the mother of invention, curiosity is 

 almost certainly its father " (A. D. Darbishire : A New 

 Biology. Cassell, 1917). The taking advantage of the 

 discoveries of Science has been prompted by the wide- 

 spread desire for ' wealth,' security, comfort, and 

 pleasure. Similarly the great steps that Man has taken, 

 especially since Pasteur's day, in the control of disease, 

 have been largely due to sheer scientific inquisitiveness, 

 but they have been prompted also by Man's sympathy 

 with and dislike of suffering. Man's shrinking from 

 disease or desire to be rid of it probably still supplies 

 a stronger motive than his ambition to be positively 

 healthy. 



Let us recall a few instances of Man's control of dis- 

 ease. The story of the mastery of malaria, for instance, 

 is like an illumined picture, and we cannot help wonder- 

 ing that it does not move men more. Laveran discovers 

 the minute animal that causes the mysterious disease. 

 Major Ross discovers that its early stages are passed 



