THE MURDEROUS CAT 211 



purr. Why should yo' kill my cat to save yo' 

 bird?" 



This was a poser. Shan turned a troubled look 

 on his uncle. 



**I reckon," he admitted slowly, ''I don't know 

 how to answer that — unless," he added, a bright 

 idea striking him — ''unless it's because my bird is 

 helping the community and your cat is injuring 

 It." 



"Go on," said Bulk 



"Well," said Shan slowly, groping for ideas 

 as he went along, "supposing your cat does kill on 

 an average a dozen birds a year and lives ten 

 years. That means he has killed at least a hun- 

 dred and twenty birds, doesn't itT' 



"Go on," came the recurring reply. 



"All right," said Shan, feeling himself on firmer 

 ground. "Half those birds, anyway, would be 

 the kind of birds useful to farmers. A bird eats 

 eight thousand million insects a season, and lives 

 about five years, so that every insect-eating bird 

 gets rid of forty billion insects in his lifetime. If 

 your cat has eaten fifty insect-eating birds, it's just 

 the same as if you'd given a permit to two trillions 

 of injurious bugs and beetles. 



"Now some insects have huge families. The 



