54 The Great World's Farm 



in that time four frogs, three small birds, two fish, one 

 mole, two grasshoppers, the entrails of a fish, and two 

 pieces of ox-liver. But even rabbits are not too large for 

 them; and one foreign species will bury a snake in a few 

 hours. 



QUESTIONS FOR REVIEW 



1. What is necessary for soil beside mineral substances? 



2. How has the soil been enriched in past ages? 



3. What services do burrowing animals render? 



4. Give instances of the diffusion of these animals. 



5. What is the case for and against the mole? 



6. Show how the crabs improve the soil. 



7. Describe the field labors of various kinds of beetles. 



