It is doubtful whether the treatise in which this theory is fully expounded is as old as Hippocrates himself; but it was regarded as a Hippocratic doctrine, and, when taken up and expanded by Galen, its terms not only became the common property of the profession, but passed into general literature and common language.
It is here that the real continuation and development of Hippocratic medicine can be traced.
The work of Celsus is thus for us only second in importance to the Hippocratic writings and the works of Galen; but it is valuable rather as a part of the history of medicine than as the subject of that history.
But they often show much practical experience, and exhibit the naturalistic method of the Hippocratic school.
The revival of Galenic and Hippocratic medicine, though ultimately it conferred the greatest benefits on medical sciences, did not immediately produce any important or salutary reform in practical medicine.