THE ANATOMY OF GALEN 29
the body, as he understood them, and, in the words of Dr. Greenhill, is a truly noble work. Besides these there are smaller works on special parts of anatomy and physiology ; and one controversial book, De Placitis Hippocratis et Platonis, directed against the Stoics and Peripatetics (or Aristotelians), is of importance as showing his methods of proof and argument. This work is quoted by Harvey?.
It must be remembered that Galen’s own dissections were made entirely on animals, the dissection of the human body being then quite impossible. Probably he had occa- sionally a glimpse of the internal organs in man, but his own remarks show that it could only have been a hurried inspection. This fact is the cause of a large number of the anatomical errors detected by Vesalius in Galen’s works, such as the description of a rete mirabile in the human skull, of the origin of the two carotids from a single stem, and many others. In one really important instance, that of the supposed perviousness of the ventricular septum, which is often quoted as one of his startling errors, he does apparently allow deduction to take the place of observation. It was evident that the blood must somehow pass from the right to the left side of the heart; and, being ignorant of the long circuit by the lungs, the old anatomists inferred a short circuit through the heart itself. Vesalius, though he could find no opening between the ventricles, inferred that there must be a communication by channels too small to be visible. Probably they were confirmed in this error
1 This treatise, though largely philosophical, and intended to show the agreement of Hippocrates and Plato: in points on which they both differed from Aristotle, contains much that is important in relation to Galen’s physiology. It is quoted by Harvey (De Motu Cordis, cap. v.). This reference, curiously enough, enables us to identify the Latin edition of Galen’s works used by Harvey. In the complete Latin editions, published at Venice by the Juntine press, and at Basel by Froben
and his successors, the title of this work, Mepl r@v ‘Imvoxparous rat TIAd- ravos Soypdarev, was translated De Decretts Hippocratis, &c. But in the Latin edition printed at Paris in 1534 the title runs De Placitis, &c. We must conclude therefore that this was the edition which Harvey used, It appears to be somewhat rare; but a copy is in the library of the Royal College of Physicians: whether it was Harvey’s own copy we cannot say. This is not a com- plete edition of Galen’s works,
