Of the two chief objects of his censure in the Natural Faculties, Galen deals perhaps less rigorously with Erasistratus than with Asclepiades. Erasistratus did at least recognize the existence of a vital principle in the organism, albeit, with his eye on the structures which the scalpel displayed he tended frequently to forget it. The researches of the anatomical school of Alexandria had been naturally of the greatest service to surgery, but in medicine they sometimes had a tendency to check progress by diverting attention from the whole to the part.
The
Pneuma
or Spirit. Another novel conception frequently occurring in Galen’s writings is that of the Pneuma (i.e. the breath, spiritus). This word is used in two senses, as meaning (1) the inspired air, which was drawn into the left side of the heart and thence carried all over the body by the arteries; this has not a few analogies with oxygen, particularly as its action in the tissues [Pg xxxv] is attended with the appearance of the so-called “innate heat.” (2) A vital principle, conceived as being made up of matter in the most subtle imaginable state (i.e. air). This vital principle became resolved into three kinds: (a) πνεῦμα φυσικόν or spiritus naturalis, carried by the veins, and presiding over the subconscious vegetative life; this “natural spirit” is therefore practically equivalent to the φῦσις or “nature” itself. (b) The πνεῦμα ζωτικόν or spiritus vitalis; here particularly is a source of error, since the air already alluded to as being carried by the arteries tends to be confused with this principle of “individuality” or relative autonomy in the circulatory (including, perhaps, the vasomotor) system. (c) The πνεῦμα ψυχικόν or spiritus animalis (anima = ψυχή), carried by longitudinal canals in the nerves; this corresponds to the ψυχή.
This view of a “vital principle” as necessarily consisting of matter in a finely divided, fluid, or “etheric” state is not unknown even in our day. Belief in the fundamental importance of the Pneuma formed the basis of the teaching of another vitalist school in ancient Greece, that of the Pneumatists.
Galen and
the Circulation
of the
Blood. It is unnecessary to detail here the various ways in which Galen’s physiological views differ from those of the Moderns, as most of these are noticed in footnotes to the text of the present translation. His ignorance of the circulation of the blood does not lessen the force of his general physiological conclu[Pg xxxvi]sions to the extent that might be anticipated. In his opinion, the great bulk of the blood travelled with a to-and-fro motion in the veins, while a little of it, mixed with inspired air, moved in the same way along the arteries; whereas we now know that all the blood goes outward by the arteries and returns by the veins; in either case blood is carried to the tissues by blood-vessels, and Galen’s ideas of tissue-nutrition were wonderfully sound. The ingenious method by which (in ignorance of the pulmonary circulation) he makes blood pass from the right to the left ventricle, may be read in the present work ([p. 321]). As will be seen, he was conversant with the “anastomoses” between the ultimate branches of arteries and veins, although he imagined that they were not used under “normal” conditions.
Galen’s
Character. Galen was not only a man of great intellectual gifts, but one also of strong moral fibre. In his short treatise “That the best Physician is also a Philosopher” he outlines his professional ideals. It is necessary for the efficient healer to be versed in the three branches of “philosophy,” viz.: (a) logic, the science of how to think; (b) physics, the science of what is—i.e. of “Nature” in the widest sense; (c) ethics, the science of what to do. The amount of toil which he who wishes to be a physician must undergo—firstly, in mastering the work of his predecessors and afterwards in studying disease at first hand—makes it absolutely necessary that he should [Pg xxxvii] possess perfect self-control, that he should scorn money and the weak pleasures of the senses, and should live laborious days.
Readers of the following pages will notice that Galen uses what we should call distinctly immoderate language towards those who ventured to differ from the views of his master Hippocrates (which were also his own). The employment of such language was one of the few weaknesses of his age which he did not transcend. Possibly also his mother’s choleric temper may have predisposed him to it.
The fact, too, that his vivisection experiments (e.g. pp. [59], [273]) were carried out apparently without any kind of anaesthetisation being even thought of is abhorrent to the feelings of to-day, but must be excused also on the ground that callousness towards animals was then customary, men having probably never thought much about the subject.
Galen’s
Greek Style. Galen is a master of language, using a highly polished variety of Attic prose with a precision which can be only very imperfectly reproduced in another tongue. Every word he uses has an exact and definite meaning attached to it. Translation is particularly difficult when a word stands for a physiological conception which is not now held; instances are the words anadosis, prosthesis, and prosphysis, indicating certain steps in the process by which nutriment is conveyed from the alimentary canal to the tissues.
Readers will be surprised to find how many words are used by Galen which they would have thought had been expressly coined to fit modern conceptions; thus our author employs not merely such terms as physiology, phthisis, atrophy, anastomosis, but also haematopoietic, anaesthesia, and even aseptic! It is only fair, however, to remark that these terms, particularly the last, were not used by Galen in quite their modern significance.