GALEN OF PERGAMUM, ON THE DIFFERENCES OF DISEASES, BOOK ONE.

A woodcut depicts a decorative capital letter V featuring a classical scene with figures in a pastoral landscape.

ALL PEOPLE consider themselves healthy when they make excellent use of the functions of their life through the service of their parts. But they judge that part to be diseased whose operation has been harmed. Therefore, since

In what things health is to be investigated.

health must be investigated either in the operations themselves or in the fabric of the instruments, it is manifest that disease is the injury of either the operation or the structure.

Disease is the injury of either operation or structure.

Furthermore, health must be defined not by the act of operation, but rather by the aptitude for it. Health therefore exists as a kind of moderation, while disease, being contrary to health, consists in the immoderation of those things of which health is the moderation.

Health is defined by the aptitude of operation, and it exists as moderation.

However, since the bodies of animals are susceptible to more and less, and can suffer and be altered (which could not happen if they consisted of a single element or of atoms not subject to any alteration), they will contract as many kinds of simple diseases as there are elements from which they are composed.

Of what things disease is called the immoderation.

For composition and formation are found in a threefold way in the body. The first is of similar parts, such as arteries, veins, bone, nerve, cartilage, ligament, membrane, and flesh. The second is of instrumental parts, such as the brain, the heart, and similar organs. The third is of the whole body.

The kinds of simple diseases are as many as the simple elements.

For the body consists of instrumental parts; instrumental parts consist of similar parts; and these finally consist of the simplest elements.

The composition of our body is threefold.