In fig. 7 we have seen a representation of the harmless Keres, the souls fluttering out of the grave-pithos. Fortunately ancient art has also left us a representation of a baleful Ker. The picture in fig. 17 is from a pelike[419] found at Thisbe and now in the Berlin Museum[420]. Heracles, known by his lion skin and quiver, swings his rudely hewn club (κλάδος) against a tiny winged figure with shrivelled body and distorted ugly face. We might have been at a loss to give a name to his feeble though repulsive antagonist but for an Orphic Hymn to Heracles[421] which ends with the prayer: ‘Come, blessed hero, come and bring allayments Of all diseases. Brandishing thy club, Drive forth the baleful fates; with poisoned shafts Banish the noisome Keres far away.’ The primitive Greek leapt by his religious imagination to a forecast of the truth that it has taken science centuries to establish, i.e. the fact that disease is caused by little live things, germs—bacilli we call them, he used the word Keres. A fragment of the early comic poet Sophron[422] speaks of Herakles throttling Hepiales. Hepiales must be the demon of nightmare, well known to us from other sources and under various confused names as Ephialtes, Epiales, Hepialos. The _Etymologicon Magnum_[423] explains ‘Hepialos’ as a shivering fever and ‘a daimon that comes upon those that are asleep.’ It has been proposed to regard the little winged figure which Herakles is clearly taking by the throat as Hepiales[424], demon of nightmare, rather than as a Ker. The question can scarcely be decided, but the doubt is as instructive as any certainty. Hepiales is a disease caused by a Ker; i.e. it is a special form of Ker, the nightmare bacillus. Blindness also was caused by a Ker, as was madness; hence the expression ‘casting a black Ker on their eyes[425].’ Blindness and madness, blindness of body and spirit are scarcely distinguished, as in the blindness of Oedipus; both come of the Keres-Erinyes.