FAMILIES IN BIRD WORLD. 



THERE are often families of people, the children 

 of which resemble one or both parents so closely 

 that any one knowing the parents is able to recognize 

 the children. This resemblance of parent and child 

 is due to the law of inheritance. Children will be like 

 their parents all through nature. 



There is, however, another law not so easy to under- 

 stand as the law of inheritance, according to which 

 two children of the same parents will differ from each 

 other in a thousand little ways. We can see this very 

 easily among our friends ; brothers and sisters are 

 alike and yet different. Only in very rare cases is it 

 hard to tell them apart. This law also holds true 

 throughout nature, and though it is often hard for 

 our eyes to see differences among animals, it is easy 

 to see in a litter of pups or a family of kittens how 

 different in size, marking, and disposition the differ- 

 ent individuals are. 



These two laws have been at work in the world for 

 ages, and between them, and with the help of one or 

 two other laws, the earth has been peopled with a 

 wonderful multitude of plants and animals of all kinds. 



Students of natural history, by looking for resem- 



