Yet while _Criton_, as cited in _Aëtius_, simply and quite correctly interpreted Mentagra by ἄγριος λειχὴν (fierce, malignant lichen), _Galen_ appears to have been still ignorant of the special meaning. This is shown by the words ἥμερος and πρᾳότερος (gentle, benignant,—milder), which obviously are correct opposites of ἄγριος only _if_ the latter is understood, as it is in _Celsus_, as equivalent to _ferus_ (fierce, malignant), but in no way account for the ἁπλοῦς (simple, innocent), which Galen no doubt found already established as distinguishing epithet of λιχὴν. How little he fathomed the nature of the evil, is proved by his ætiology of it, which makes the complaint result from the φλέγμα ἁλμυρὸν (salt phlegmatic humour) and the χολὴ ξανθὴ (yellow gall). The unprofessional _Martial_ had a better word to say on the subject when he wrote his _sordidique lichenes_ (filthy, squalid-looking lichens). Similarly it would seem the _agra_ in Mentagra should be taken as pointing to ἄγριος (fierce, malignant). Can it be perhaps that in this way the μολύνων τὴν ὑπήνην (polluting the hair on the upper lip) of _Aristophanes_, the Latin _barbam inquinare_ (to pollute the beard), have come to be used as synonyms for _cunnilingere_? _Martial_ seems to imply it by his _triste mentum_, _mentum periculosum_ (disfigured chin, perilous chin). Perhaps too the _Sycosis menti_ (Sycosis,—fig-like eruption, of the chin) of _Celsus_ and the later Greek medical writers should likewise be regarded as coming under this head. At a matter of fact, _Archigenes_ says so in so many words, as cited in _Galen_ (De comp. med. secundum locos. Bk. V. edit. Kühn Vol. XII. p. 847.), ἐπὶ δὲ τῶν _συκωδῶν τῶν ἐπὶ τοῦ γενείου, λεγομένων δὲ μενταγρῶν, ὑπὸ δέ τινων λειχήνων ἀγρίων_, ποιεῖ κ. τ. λ. (but in the case of the sycotic, or fig-like, eruptions on the chin, which are called mentagrae, and by others malignant lichens, he proceeds as follows, etc.), and calls the affection of the chin, as do other Physicians, generally ἐξανθήματα ἐν τοῖς γενείοις (efflorescences, eruptions on the chin),—p. 824. If we have thus succeeded in establishing the meanings of _lichens_ and _mentagra_, the rest of the passage of _Pliny_ will admit of easy explanation. The disease in many cases it seems invaded the whole face, in the same way as the _atra lues_ (black contagion) in the passages quoted above from _Martial_ under _fellation_. Perhaps all of these,—indeed, _Pliny_ also says _lues_,—are the be referred, as is actually done by _Farnabius_ in his notes, to _mentagra_, seeing that the disease could perfectly well, though certainly much seldomer, arise equally from the practise of _fellation_. The _double entendre_ between _mentum_ (the chin) and _menta_ or _mentula_ (the virile member) would so acquire all the more point.