52 ODD HOURS WITH NATURE 



which is of no such dependant nature. If it existed 

 at all in the time of palaeolithic man, who was 

 a hunter, it must have been a very moderate 

 success indeed. The psychological modification 

 which marks it off from all the other finches, 

 and is its real distinction, could have been of no 

 survival value to it, but when neolithic man, the 

 cultivator, came in, Mr. Sparrow got his chance. 

 His case is like that of the sub-species of man, 

 flourishing greatly to-day, distinguished by pre- 

 eminent ability to operate successfully on the 

 Stock Exchange. There were doubtless always 

 men with this talent embedded in their brains, but 

 it was no use to them a worthless modification 

 through all the ages of simple industry. They 

 got their chance for the first time when Stock 

 Exchanges were invented. 



I have said that there is something of that 

 precariousness in the position of the house-sparrow 

 incident to the position of all parasites. The 

 success of a parasite always depends on the 

 success of its host, and if the host discover a 

 means of guarding itself the parasite's day is done. 

 The sparrow's human host seems in a fair way 

 to survive, but if he made up his mind that 

 the sparrow was seriously injurious to him and 

 must be extirpated, the work of extirpation would 

 not be really difficult. If an order were issued for 

 the destruction of almost any one of the finches 

 it would be extremely difficult to carry it out. They 

 are not easily found when wanted, and their nests, 

 without exception, are well hid. The nests of 

 the house-sparrow, on the other hand, are always 



