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 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). 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. [Sidenote: 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 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_) [Greek: pneuma physikon] or _spiritus naturalis_, carried by the veins, and presiding over the subconscious vegetative life; this "natural spirit" is therefore practically equivalent to the [Greek: physis] or "nature" itself. (_b_) The [Greek: pneuma zôtikon] 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 [Greek: pneuma psychikon] or _spiritus animalis_ (anima = [Greek: psychê]), carried by longitudinal canals in the nerves; this corresponds to the [Greek: psychê].