As a type of characteristically vital action we may take nutrition, in which occurs a phenomenon [Pg xxix] which Galen calls active motion (δραστικὴ κίνησις) or, more technically, alteration (ἀλλοίωσις). This active type of motion cannot be adequately stated in terms of the passive movements (groupings and re-groupings) of its constituent parts according to certain empirical “laws.” Alteration involves self-movement, a self-determination of the organism or organic part. Galen does not attempt to explain this fundamental characteristic of alteration any further; he contents himself with referring his opponents to Aristotle’s work on the “Complete Alteration of Substance” ([p. 9]).
The most important characteristic of the Physis or Nature is its τέχνη—its artistic creativeness. In other words, the living organism is a creative artist. This feature may be observed typically in its primary functions of growth and nutrition; these are dependent on the characteristic faculties or powers, by virtue of which each part draws to itself what is proper or appropriate to it (το οἰκεῖον) and rejects what is foreign (το ἀλλότριον), thereafter appropriating or assimilating the attracted material; this assimilation is an example of the alteration (or qualitative change) already alluded to; thus the food eaten is “altered” into the various tissues of the body, each of these having been provided by “Nature” with its own specific faculties of attraction and repulsion.
The Three Categories. Any of the operations of the living part may be looked on in three ways, either (a) as a δύναμις, [Pg xxx] faculty, potentiality; (b) as an ἐνέργεια, which is this δύναμις in operation; or (c) as an ἔργον, the product or effect of the ἐνέργεια.[3]
[Pg xxxi] Galen’s
Method. Like his master Hippocrates, Galen attached fundamental importance to clinical observation—to the evidence of the senses as the indispensable groundwork of all medical knowledge. He had also, however, a forte for rapid generalisation from observations, and his logical proclivities disposed him [Pg xxxii] particularly to deductive reasoning. Examples of an almost Euclidean method of argument may be found in the Natural Faculties (e.g. Book III. [chap. i.]). While this method undoubtedly gave him much help in his search for truth, it also not unfrequently led him astray. This is evidenced by his attempt, already noted, to apply the biological principle of the φύσις in physics. Characteristic examples of attempts to force facts to fit premises will be found in Book II. [chap. ix]., where our author demonstrates that yellow bile is “virtually” dry, and also, by a process of exclusion, assigns to the spleen the function of clearing away black bile. Strangest of all is his attempt to prove that the same principle of specific attraction by which the ultimate tissues nourish themselves (and the lodestone attracts iron!) accounts for the reception of food into the stomach, of urine into the kidneys, of bile into the gall-bladder, and of semen into the uterus.
These instances are given, however, without prejudice to the system of generalisation and deduction which, in Galen’s hands, often proved exceedingly fruitful. He is said to have tried “to unite professional and scientific medicine with a philosophic link.” He objected, however, to such extreme attempts at simplification of medical science as that of the Methodists, to whom diseases were isolated entities, without any relationships in time or space (v. [p. xv]. supra).
He based much of his pathological reasoning upon [Pg xxxiii] the “humoral theory” of Hippocrates, according to which certain diseases were caused by one or more of the four humours (blood, phlegm, black and yellow bile) being in excess—that is, by various dyscrasiae. Our modern conception of “hormone” action shows certain resemblances with this theory.
Besides observation and reasoning, Galen took his stand on experiment; he was one of the first of experimental physiologists, as is illustrated in the present book by his researches into the function of the kidneys ([p. 59] et seq.). He also conducted a long series of experiments into the physiology of the spinal cord, to determine what parts controlled movement and what sensibility.
As a practitioner he modelled his work largely on the broad and simple lines laid down by Hippocrates. He had also at his disposal all the acquisitions of biological science dating from the time of Aristotle five hundred years earlier, and reinforced by the discoveries in anatomy made by the Alexandrian school. To these he added a large series of researches of his own.
Galen never confined himself to what one might call the academic or strictly orthodox sources of information; he roamed the world over for answers to his queries. For example, we find him on his journeys between Pergamos and Rome twice visiting the island of Lemnos in order to procure some of the terra sigillata, a kind of earth which had a reputation for healing the bites of serpents and [Pg xxxiv] other wounds. At other times he visited the copper-mines of Cyprus in search for copper, and Palestine for the resin called Balm of Gilead.
By inclination and training Galen was the reverse of a “party-man.” In the Natural Faculties ([p. 55]) he speaks of the bane of sectarian partizanship, “harder to heal than any itch.” He pours scorn upon the ignorant “Erasistrateans” and “Asclepiadeans,” who attempted to hide their own incompetence under the shield of some great man’s name (cf. [p. 141]).