42 The Cannibal Habit in the Male 



the annual destruction by the fishing-net, great as it is, 

 is balanced by the number of young cod saved from 

 death. 



The potentiality of increase of prolific species shows 

 its actual power in a startling manner when the condi- 

 tions of life by man's intervention are altered. Take, 

 as an illustration, the introduction of the rabbit into 

 Australia. Its fecundity is so enormous that man 

 would find it difficult to keep its number within due 

 bounds, even in Great Britain, were it not that the far 

 greater number of the broods are destroyed by the 

 males, as all schoolboys know by bitter experience. 

 When this animal was introduced into Australia the 

 conditions of life were wholly changed ; there were 

 few carnivora to destroy them, while illimitable space 

 was afforded by the female on every side to enable her 

 to hide her brood from the ken of the male. Accord- 

 ingly it multiplied and spread with the rapidity of wild- 

 fire, causing disastrous results to the agriculturists. 



From a consideration of these observed phenomena 

 of nature we are now able to state that the theory of 

 Darwin does not rest on proved scientific data, and are 

 entitled to say that his " checks " upon increase of 

 population can no longer be held to be, in his own 

 words, " most obscure." 



