downing] A SCHOOL OUTLINE 231 



Lesson XIV. The Hind Leg. — Notice the cat's hind 'leg. 

 How many joints does it have? Feel it carefully and see. How 

 do these joints compare in number and position with those of 

 the fore-leg? Study the hind-leg of the dog, squirrel and rabbit. 

 Compare with that of the cat. Have the children sketch the hind 

 leg and reduce to diagrams in the same way as already described 

 for the fore-leg. Now let the children write a description of 

 what they have each observed regarding the structure of 

 the fore and hind legs of these animals. To hold one set 

 of facts in mind and compare it with another and still an- 

 other and finally with a whole series ; to see a fundamental unity 

 underlying superficial differences is to take a step in advance 

 of mere observation. The goal will be reached when the 

 children see for themselves that the legs of these several animals 

 are built upon the same plan. The fact is not the goal, but hav- 

 ing the children see for themselves is the desirable achievement. 



Lesson XV. Vertebrates. — Let the children feel of the 

 cat and dog to gain an idea of the skeleton. Feel the vertebral 

 column, extending from head to tip of tail. Do horses and cows 

 have a back bone? Do we? What other animals that you know 

 have a back bone? Continue such question to lead the pupils to 

 see that the back bone is characteristic of a great many animals, 

 the vertebrates. Feel the ribs and breast bone ; then note that the 

 head is a bony mass. Feel the shoulder blade that fastens the 

 foreleg to the body. When the cat is not standing on her feet, 

 this bone, to which the foreleg is attached, may be easily moved 

 about as it is simply imbedded in. the muscle, not fastened to the 

 other bones. Have the children demonstrate this to their own 

 satisfaction. Feel the hip bone, to which the hind legs attach 

 and which fastens, in turn, to the vertebral column. Are there 

 bones in the legs? What is their relation to the joints that we 

 have noted and diagrammed ? Why does a cat have bones ? Does 

 an oyster have bones ? 



Is a cat's hind leg straight like yours? Have some of the 

 children jump to show how the leg is bent in the process. Now, 

 can you tell why the cat's hind leg is always bent so k ? Watch 

 the cat jump down from a table. How does she use the hind 

 legs? On which legs does- she alight? How does the way in 

 which the foreleg is attached to the body make it easy for her 

 to alight? How could the structure of the legs help the cat in 

 hunting? Which has straighter legs, a dog or a cat? A horse 

 or a cat? Which can run faster? Think of other animals that 

 can run fast and far. Do they have straight legs or legs bent 

 like the cat's hind leg? Make a list of the very speedy animals 



