122 PROBLEMS OF BIRD LIFE. 



First, you would throw all the beans into one dish and all 

 the peas into another ; then you would take one of these dishes 

 and separate the plain white beans from the spotted ones, and 

 finally you would sort out the white bush beans from the 

 white limas, and the spotted yellow-eyes from the streaked 

 cranberry beans, putting each by itself. You would have 

 classified the beans. Then you would classify the peas in the 

 same way. To classify means to sort out into kinds. 



Now this is what the scientist would do with his ten thou- 

 sand specimens. He would classify them. For convenience 

 and exactness he would first divide them into but two classes, 

 each of which he would divide again and again into two more 

 classes, until at last he had separated each kind out by itself. 

 It is never safe to divide into more than two classes at a step 

 for fear of making some mistake. 



In his classification the scientist would try to find out the 

 plans on which these creatures were made. With the peas 

 and beans you very rightly judged that there was something 

 within the seed more important than the shape or color of it, 

 and you soon saw that the kidney shape of the bean and the 

 globular shape of the pea stood for that difference within 

 them was the index, as we say, of the plan on which each 

 was made, while the size and color only served to tell bean 

 from bean, and pea from pea. 



In the same way the scientist studies his animals to find 

 out the plan on which each is made and the index of that 

 plan. He finds two great divisions which are well marked 

 by a number of differences, among others by having, or not 

 having, bones. It seems to him that bones are the index to 

 two distinct kinds of life, so he culls out all the shellfish, 

 worms, spiders, insects, and other boneless creatures into 

 a group by themselves. Those with bones he puts into 



