The brain of man, like that of all animals is double, being parted down its centre by a thin membrane. For this reason pain is not always felt in the same part of the head, but sometimes on one side, sometimes on the other, and occasionally all over.

Many admire, few know.

I am about to discuss the disease called 'sacred'. It is not, in my opinion, any more divine or more sacred that other diseases, but has a natural cause, and its supposed divine origin is due to men's inexperience, and to their wonder at its peculiar character.

The human body contains blood, phlegm, yellow bile and black bile. These are the things that make up its constitution and cause its pain and health. Health is primarily that state in which these constituent substances are in the correct proportion to each other, both in strength and quantity, and are well mixed.

It is changes that are chiefly responsible for diseases, especially the greatest changes, the violent alterations both in the seasons and in other things. (:)...regimen and temperature, and one period of life to another.

The function of protecting and developing health must rank even above that of restoring it when it is impaired.

There are in fact two things, science and opinion. The former begets knowledge, the latter ignorance.