But still, while finding time for services to other men, he could produce as much out of his own study as though he had no part in the life beyond its walls." A large majority of these early naturalists and botanists were physicians.( 3) The Greek art of observation was revived in a study of the scientific writings of Aristotle, Theophrastus and Dioscorides and in medicine, of Hippocrates and of Galen, all in the Greek originals.
That progress was at first slow was due in part to the fact that the leaders were too busy scraping the Arabian tarnish from the pure gold of Greek medicine and correcting the anatomical mistakes of Galen to bother much about his physiology or pathology.

Here and there among the great anatomists of the period we read of an experiment, but it was the art of observation, the art of Hippocrates, not the science of Galen, not the carefully devised experiment to determine function, that characterized their work.

There was indeed every reason why men should have been content with the physiology and pathology of that day, as, from a theoretical standpoint, it was excellent.

The doctrine of the four humors and of the natural, animal and vital spirits afforded a ready explanation for the symptoms of all diseases, and the practice of the day was admirably adapted to the theories.

There was no thought of, no desire for, change.