There are very few modern text books in which the author treats the subject in as exhaustive a manner as Galen has done in these seventeen books. As may readily be imagined from the great number and length of his writings, he often wanders off into side issues and thus lays himself open to the charge of being a diffuse writer. At the same time he cannot be accused of dullness, for in reading Daremberg’s version one is seldom tempted to omit any of the text, and his style is interesting. The following brief extracts, to which should be added that given on a previous page, may be taken as fair samples of his manner of treating questions in the department of physiology:-- _Reasons why the Alae Nasi are Cartilaginous and why they may be Moved by Voluntary Muscular Action._--We have already explained in some measure the reasons why the alae nasi should be composed of cartilage and why it should be possible for the animal to move them at will.[41] It is an established fact that the movements of these parts are competent to aid in no small degree the somewhat forcible inspirations and expirations. This is the reason why the alae are constructed in such a manner as to be easily movable. They are made of cartilage because this substance is hard to fracture or to tear apart. The placing of these alar movements under the control of the will, and not under that of some other bodily force (like the arterial impulse, for example), is certainly an excellent arrangement; and, if one does not appreciate this without any further explanation, it must be because my previous reasonings about such matters have fallen upon inattentive ears. (Translated from Book XI., Chapter XVII., of Daremberg’s French version of Galen’s works.) Another brief extract may be given here. It forms a part of the chapter relating to the action of the sigmoid valves of the pulmonary artery, etc., and merits special attention because it furnishes additional evidence of the correctness of Daremberg’s statement that Galen was the leader of the most advanced school of experimentation:-- The more strongly the thorax, in its exertion of a compressing force, tends to drive the blood (out of the heart), the more tightly do these membranes (the sigmoid valves) close the opening. Invested in a circular manner from within outward, extending throughout the entire circumference of the interior of the vessel, these membranous valves are, each one of them, so accurately patterned and so perfectly fitted that when they are put upon the stretch by the column of blood, they constitute a single large membrane which closes (watertight) the orifice. Pushed back by the return flow of the blood, they fall back against the inner surface of the vein, and permit an easy passage of the blood through the amply dilated orifice (which they, an instant before, closed so perfectly).