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THE BODY AT WORK

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Physiology is the science of the body at work. It is the study of life. Anatomy records how plants and animals are constructed. It maps and measures. Physiology ascertains what they do, endeavours to explain how they do it, and conjectures why.

A knowledge of structure is essential to the right understanding of function; but the physiologist does not contemplate structure with a view to divining possibilities of action. He has no interest in structure as such. To him it is a matter of perfect indifference whether the tendon of a muscle is at its origin or its insertion. He would rather not know which end of the muscle terminates in a tendon. It is waste of his time to notice such a fact, save for the negative, the protective value of the information. If he did not know how the muscle and tendon are related, he might possibly imagine the muscle as doing something of which it is incapable. Observers of living things are often credited with studying structure with a view to determining function. The reverse is the true order of thought and observation. Living things perform certain acts. Having no inherent knowledge of our own microcosm which enables us to say how it works, we cannot, by reflecting upon our own internal operations, explain its various activities. Nor can we make use of the results of introspection when endeavouring to account for the acts of other beings. Our knowledge of how things are done is altogether extrapersonal, objective. It is the result of trial, failure, success in the use of apparatus, our own essays, or those of others. The body is a combination of organs—a term used somewhat loosely to designate any piece of the animal mechanism which has a distinct function to perform. The physiologist studies the results of the activity of an organ. He watches it in action, and endeavours to explain the process by which it produces its effects. Then follows the anatomist, who, taking it to pieces, examines it with the utmost thoroughness which scalpel and forceps or microscope allows, with a view to ascertaining whether its structure will support the physiologist’s hypothesis as to its mode of action. This in the vast majority of cases has been the history of scientific progress. The physiologist has preceded the anatomist in drawing inferences as to the manner in which things are done. The anatomist, after a further examination of structure, has either admitted the plausibility of his explanation, or has interposed the objection that the part was incapable of working in the way supposed.