HOW THE ANIMAL BODY IS FORMED 1 3 



contact with the blood in the lungs. Oxygen is in 

 reality absorbed, and on the blood leaving the lungs 

 it is distributed to all parts of the body. The oxy- 

 gen supply of the body is, therefore, in the keeping 

 of the red corpuscles. 



White corpuscles have a different work ; they 

 guard the body by picking up poison, bacteria, and 

 other undesirable elements and cast these out 

 through the natural openings of the body. Com- 

 pared with the red cells, they exist in far less num- 

 bers and may wander about through all parts of 

 the body. 



Lymph is a fluid in which a few cells, lymph 

 corpuscles, are suspended. These cells are very 

 much like the colorless corpuscles of the blood, 

 only no red blood cells are present. But the lymph 

 attends to its own business; it bathes the tissues 

 and endeavors to keep them in a healthy condition. 



Skin and Hair. — Without a covering the delicate 

 muscles would be unprotected. The skin serves in 

 this capacity. It does still more; out of it is 

 exuded poisonous substances, perspiration, and, at 

 the same time, the skin is a sort of respiratory 

 organ, through which much of the carbonic acid 

 formed in the body escapes. 



The skin possesses two general layers, the cutis 

 and sub-cutis; in the first is contained also 

 epidermis. Developed in the skin are the outer 

 coverings like hair, wool, feathers, horns, claws, 

 and hoofs. 



THE FRAMEWORK OF THE BODY 



The framework of the body undergoes a gradual 

 development from birth to maturity. It represents 

 the bony structure of the body ; and on it all other 



