This entry is un uncomfortable condensation of a badly-transmitted passage of Alexander of Aphrodisias [OCD(4) p.59, 'Alexander(14)'; RE 1.1453-55 'Alexandros 94'), Commentary on Aristotle's Topica 430.13-23 Wallies (Comm. in Aristot. Graeca 2, part ii, 1891), commenting on the following passage of Aristotle about avoiding superfluous words in definition: "As, for example" (introducing an illustration of the point about inaccurate definitions), "the definition of phlegm as 'the moisture that comes first undigested from food.' For one thing is first, not many things; as a result the added word 'undigested' is superfluous. For, when it is removed, the rest is an appropriate statement; for it is not admissible either that from food both phlegm and something else be first, or that phlegm is absolutely first from food, but also first of undigested things, with the result that 'undigested' must be added [to the definition], for the logic of the definition stated in those ways is not correct, unless phlegm is first of all things" (Topica 140b7-15 Ross; cf. the rather different translation, on which this is based, by A.W. Pickard-Cambridge in Complete Works of Aristotle, ed. J. Barnes, Princeton, 1984, vol. 1 p.237). The definition reflects a well-known problem with Aristotle's concept of causality.
Although Aristotle's point concerns the propriety of the use of 'first' in definitions expressing cause and result, it reflects his view of the four 'humours' (OCD(4) 712-13) as body fluids responsible for various diseases, e.g. de Partibus Animalium 2.7.652b33-3a20; Problemata §1.9.860a23-32 (on winter catarrh), 29.862b27-32 (on autumn and winter fevers), §10.1.891a8-12 (on the mucus of coughing), §11.18.900b38-1a6 (on vomit), 61.905b38-6a2 (on the deepening of voices in winter); cf. sections on phlegm and the emission of sperm (§1.50.865a33-b5, §4.16.878a14-16, 29.880a21-29). Nicomachus, his father, had been a practitioner of Asclepiadean healing and court physician to the king of Macedon (nu 399). The dogmatic Aristotelian view of the humours in the body as causes of disease was widely accepted and developed in antiquity, e.g. in the works of the Hippocratic Corpus, esp. On the Nature of Man (see Loeb edition of "Hippocrates" vol. 4, pp. 1-41), On Affections (vol. 5.1-91) and On Internal Affections (vol. 6.65-255). Empirical science practiced by men like Erasistratus and Herophilus, who questioned the dogma, was frustrated by its authority. See the works of G.E.R. Lloyd (e.g. The Revolutions of Wisdom, Berkeley, 1987, 114-23) and R.J. Hankinson’s excellent synopsis of views of the causes of disease before Galen in his edition referred to below, 7-48.
The role of the humours, phlegm, blood, yellow bile and black bile, remained crucial in medical diagnosis and treatment until quite modern times. They gave their Greek or Latin names to types of disposition: phlegmatic, sanguine, choleric and melancholy. They were associated with the 'four elements' and 'four seasons'. Various white or clear bodily secretions were attributed to phlegm or derived from it: all mucus of sinus and gastric catarrh, sweat, tears, emissions of sperm. Etymologically, the word comes from a root for burning and inflammation (cf. flo/c, fle/gw, flegmonh/, flegmai/nw, phi 525, pi 3240, kappa 1184), and is so used in Homer (Iliad 21.337) and sometimes in medical writers (LSJ s.v.). It must have at some stage been used for discharge or pus from such inflammation, but Aristotle shows that by his day it was regarded as a cold, white, watery substance caused by the digestion -- or rather indigestion -- of food, probably imagined as the result of a fiery seething in the swollen stomach (cf. omicroniota 28, omicroniota 29, omicroniota 30, omicroniota 31, omicroniota 33).
Alexander, who must have been a younger contemporary of Galen about 190 AD, mentions the humours elsewhere only in his commentary in Metaphysica 556.23. Nothing can be told of his knowledge of later medical theories. In modern usage the word phlegm is normally restricted to the results of sinus and gastric catarrhs.
[1] See alphaiota 187.
[2] The verb here is an error and the text makes no sense. Alexander has the genitive case of the present participle, metaba/llontos, followed later in the sentence by the verb gi/netai, 'happens, comes'. The sentence should run as it does in Alexander, "From the phlegm being transformed (i.e. the transformation of the phlegm) there comes a bitter taste around the stomach."
[3] Greek xu/mos means 'juice, taste, flavour' (see LSJ s.v.). It is also the regular word in Aristotle for the four 'humours', and hence its use for a taste resulting from a transformation of the humour phlegm is curiously awkward here and in Alexander.