COVERING OF THE HOUSE. 117 



The red color is caused by the blood in them ; 

 for it is not only true that blood, in small veins 

 and arteries, runs through them in every direc- 

 tion, but it also tinges their whole substance. 

 We know this is so, because when the muscles 

 have been soaked and boiled long enough, their 

 redness disappears. Even when boiled for the 

 table, the muscular parts of animals are of a 

 paler red than they were when they were first 

 separated from the mass of flesh to which they 

 belonged. 



THE TENDONS. Some of the muscles are 

 fastened at once to the bones, and grow into 

 them. In this case the covering of the bones, 

 or periosteum, seems like a sort of glue, in- 

 tended to cement the muscle and bone together. 

 But in general, the muscles are not themselves 

 fastened to the bone. They terminate towards 

 each end, by one or more tendons. These 

 tendons are white, flattened substances, like 

 belts or straps, and are very tough and un- 

 yielding. When boiled with the muscle to 

 which they are attached, they are sometimes 

 called whit-leather ; and it is almost as difficult 



