independent living thing, an organ that in certain conditions might live and work by itself. It has its own blood-vessels for supplying it with nourishment, its own nerves for stimulating it to activity, or for putting it into relation with the headquarters in the nervous system, and its own arrangements for the removal of so-called waste matters that have arisen from the tear and wear of the muscle in its active life.
Now, suppose we could isolate a muscle from the rest of the body and keep it alive, you can see that we might be able to examine the changes that occur in it when it works. So long as it is in the body, we cannot easily subject it to the method of experimental inquiry, because it is, in the first place, part of a living sentient being; and, in the next place, it is part of a complicated organism, the functions of which are all so closely connected, that if we interfere with the mechanism of one part we interfere with the whole, and this disturbance of the functions of the body as a whole reacts upon the functions of the very part we desire to study. Obviously, then, our course is to remove the muscle from the body
