104 FOUR-FOOTED AMERICANS 



Men gave liim, in addition to his English one. Tliis 

 hidder is arranged so that when you liear a story of an 

 animal, you can look at it and see in what family he 

 belongs, in what guild he works, and his place in the 

 tree. If we ever make our stories into a book w^e 

 will put this ladder at the end to help little people who 

 might not be able to climb our tree witliout it." 



'' Are those fourfoots all made into families and 

 guilds ? How is it done, by watching their claws and 

 mouths, what they eat, and the way they work, the 

 same as with the birds?" 



'^Partly," said the Doctor, laughing, ''only it is teeth 

 and feet with jNIannnals, instead of bills and claws. 



" The Wise ^len, by measuring, comparing, and 

 studying the bones of these Mammals, have divided 

 them into groups or classes, keeping those the most 

 like together. Tliis is called classification^ and is very 

 important. If they had not done this, you would never 

 guess, by looking at pictures or at stuffed animals in a 

 iMuseum, that a Whale is one of your blood brothers 

 and not a great fish ; or that the Bat, that you see 

 flitting al)()ut at twilight, is not a 1)ird." 



" I'm sure it takes a lot of believing to know that a 

 Whale isn't a fish any wa}^" said Nat. '' Do Mammals 

 have tools to work with the same as birds have chisel 

 and hooked bills and all that ? " 



"Yes, every ^lammal has either a tool or weapon, 

 and sometimes the same thing answers for both, as you 

 will see." 



"You need not trouble yourself with learning your 

 ladder by heart all at once ; but when you have heard a 

 story about an animal, go to the ladder and it will help 



