In these subjects Galen was not as proficient as Dioscorides, whose teaching he adopted with that of other medical authors. In Galen's works there are lengthy lists of compound medicines, several medicines being recommended for the same disease, and never with very marked confidence. He paid high prices for various nostrums, and, sad to relate, placed great faith in amulets, belief in which was general in his time, and nowhere held more strongly than in superstitious Rome. Medicines were classified by him according to their qualities, by which he meant, not their therapeutic effects, but their inherent dryness or moistness, coldness or heat. A medicine might be cold in the first degree, and not in the second degree. Paulus Ægineta followed this strange and foolish doctrine of Galen very closely, as the following extracts from his book on Materia Medica will show:--
"Cistus (rock-rose).--It is an astringent shrub of gently cooling powers. Its leaves and shoots are so desiccative as to agglutinate wounds; but the flowers are of a more drying nature, being about the second degree; and hence, when drunk, they cure dysenteries and all kinds of fluxes."[24]
"Ferrum (iron).--When frequently extinguished in water, it imparts a considerable desiccative power to it. When drunk, therefore, it agrees with affections of the spleen."[25]
Many features, however, of Galen's teaching and practice of therapeutics are worthy of praise. He enunciated two fundamental principles: (1) That disease is something contrary to Nature, and is to be overcome by that which is contrary "to the disease itself"; and (2) that Nature is to be preserved by what has relation with Nature. He recognized that while the invading disease was to be repelled, the strength and constitution of the patient should be preserved, and that in all cases the cause of the disease was to be treated and not the symptoms. Strong remedies should not be used on weak patients.