THE STRUGGLE FOR EXISTENCE 13 



stocked with its animal tenants for generations, if the 

 normal population of adult tigers be 200, there cannot 

 be a sufficient supply of their natural food to maintain, 

 say, 1000 additional tigers, including in that amount 

 the 200 destined to survive and 800 doomed to 

 perish. It would appear, then, that the progeny who 

 survive are those who from possessing superior in- 

 dividual variations or differences are able to get food 

 and live, and that the others fail to get the necessary 

 amount of food." 



" But, my good sir," I replied, " you must look at 

 things in the concrete, lest by thrusting your mental 

 eyes into a cloudbank of plausible abstract phrases, 

 you act like the proverbial ostrich which, when hard 

 pressed, thrusts its head into the sand and fancies it 

 has escaped its pursuers by depriving itself of the 

 power of seeing them. Make sure that your words, 

 however admirable from a Darwinian point of view, 

 are consonant with common sense and come within 

 the sphere of the possible. You assume that in a 

 limited area of jungle which can comfortably maintain 

 in the aggregate only 400 adult and young tigers, 

 there perish from inability to get the necessary food 

 1900 tigers in each generation. Yet the young 

 tigers that appear as food - seekers are preserved, 

 and have their maintenance assured to them so long 

 as they are feeble and immature, by the protect- 

 ing guardianship of their parents, and are only left 

 to their own resources when they are able to hunt 

 and kill for their own subsistence. I quite agree 



