We will now turn our attention to the force which puts this machinery in motion. If the white skin all over the body were stripped away the red flesh would be seen beneath. This red flesh is muscle. The muscles are the agents by which all movements of the body are carriedout. Wherever the greatest power of movement is required, there we willfind the largest and strongest muscles. In some parts of the body, such as in the legs and arms, the muscles are placed in large solid-looking masses around the bone. In other parts we see that the muscles extend between the bones. The skull has a very slight covering of muscle beneath theskin, for the simple reason that the bones of the skull do not move, and huge muscles are not required.
A lean piece of flesh from the body of an animal would be found on examination to consist of separate bundles of flesh, arranged side by side in such a way that each has the power of moving or sliding about independently of the rest. These separate bundles of flesh are the muscles.