Many of his physiological experiments were conducted upon scientific principles. Thus he proved that certain muscles were under the control of definite sets of nerves by cutting these nerves in living animals, and observing that the muscles supplied by them were rendered useless. He pointed out also that nerves have no power in themselves, but merely conduct impulses to and from the brain and spinal-cord. He turned this peculiar knowledge to account in the case of a celebrated sophist, Pausanias, who had been under the treatment of various physicians for a numbness in the fourth and fifth fingers of his left hand. These physicians had been treating this condition by applications of poultices to the hand itself. Galen, being called in consultation, pointed out that the injury was probably not in the hand itself, but in the ulner nerve, which controls sensation in the fourth and fifth fingers. Surmising that the nerve must have been injured in some way, he made careful inquiries of the patient, who recalled that he had been thrown from his chariot some time before, striking and injuring his back. Acting upon this information, Galen applied stimulating remedies to the source of the nerve itself–that is, to the bundle of nerve-trunks known as the brachial plexus, in the shoulder. To the surprise and confusion of his fellow-physicians, this method of treatment proved effective and the patient recovered completely in a short time.
Although the functions of the organs in the chest were not well understood by Galen, he was well acquainted with their anatomy.
He knew that the lungs were covered by thin membrane, and that the heart was surrounded by a sac of very similar tissue. He made constant comparisons also between these organs in different animals, as his dissections were performed upon beasts ranging in
size from a mouse to an elephant. The minuteness of his observations is shown by the fact that he had noted and described the ring of bone found in the hearts of certain animals, such as the horse, although not found in the human heart or in most animals.
His description of the abdominal organs was in general accurate.
He had noted that the abdominal cavity was lined with a peculiar saclike membrane, the peritoneum, which also surrounded most of the organs contained in the cavity, and he made special note that this membrane also enveloped the liver in a peculiar manner. The exactness of the last observation seems the more wonderful when we reflect that even to-day the medical, student finds a correct understanding of the position of the folds of the peritoneum one of the most difficult subjects in anatomy.
As a practical physician he was held in the highest esteem by the Romans. The Emperor Marcus Aurelius called him to Rome and appointed him physician-inordinary to his son Commodus, and on special occasions Marcus Aurelius himself called in Galen as his medical adviser. On one occasion, the three army surgeons in attendance upon the emperor declared that he was about to be attacked by a fever. Galen relates how “on special command I felt his pulse, and finding it quite normal, considering his age and the time of day, I declared it was no fever but a digestive disorder, due to the food he had eaten, which must be converted into phlegm before being excreted. Then the emperor repeated three times, ‘That’s the very thing,’ and asked what was to be done. I answered that I usually gave a glass of wine with pepper sprinkled on it, but for you kings we only use the safest remedies, and it will suffice to apply wool soaked in hot nard ointment locally. The emperor ordered the wool, wine, etc., to be brought, and I left the room. His feet were warmed by rubbing with hot hands, and after drinking the peppered wine, he said to Pitholaus (his son’s tutor), ‘We have only one doctor, and that an honest one,’ and went on to describe me as the first of physicians and the only philosopher, for he had tried many before who were not only lovers of money, but also contentious, ambitious, envious, and malignant.”[7]
It will be seen from this that Galen had a full appreciation of his own abilities as a physician, but inasmuch as succeeding generations for a thousand years concurred in the alleged statement made by Marcus Aurelius as to his ability, he is perhaps excusable for his open avowal of his belief in his powers. His faith in his accuracy in diagnosis and prognosis was shown when a colleague once said to him, “I have used the prognostics of Hippocrates as well as you. Why can I not prognosticate as well as you?” To this Galen replied, “By God’s help I have never been deceived in my prognosis.”[8] It is probable that this statement was made in the heat of argument, and it is hardly to be supposed that he meant it literally.