Dog days

[5] In Homer's Iliad, probably composed in the 8th century BC but representing an earlier tradition,[6] Achilles's approach toward Troy, where he will slay Hector, is illustrated through an extended metaphor about the baleful effects attending the return of Sirius:

τὸν δ᾽ ὃ γέρων Πρίαμος πρῶτος ἴδεν ὀφθαλμοῖσι παμφαίνονθ᾽ ὥς τ᾽ ἀστέρ᾽ ἐπεσσύμενον πεδίοιο, ὅς ῥά τ᾽ ὀπώρης εἶσιν, ἀρίζηλοι δέ οἱ αὐγαὶ φαίνονται πολλοῖσι μετ᾽ ἀστράσι νυκτὸς ἀμολγῷ, ὅν τε κύν᾽ Ὠρίωνος ἐπίκλησιν καλέουσι.

During this period, Sirius was invisible from the earth but it was apparently understood to still be in the sky, augmenting the power of the sun: ἦμος δὴ λήγει μένος ὀξέος ἠελίοιο καύματος ἰδαλίμου, μετοπωρινὸν ὀμβρήσαντος Ζηνὸς ἐρισθενέος, μετὰ δὲ τρέπεται βρότεος χρὼς πολλὸν ἐλαφρότερος: δὴ γὰρ τότε Σείριος ἀστὴρ βαιὸν ὑπὲρ κεφαλῆς κηριτρεφέων ἀνθρώπων ἔρχεται ἠμάτιος, πλεῖον δέ τε νυκτὸς ἐπαυρεῖ: τῆμος ἀδηκτοτάτη πέλεται τμηθεῖσα σιδήρῳ ὕλη, φύλλα δ᾽ ἔραζε χέει, πτόρθοιό τε λήγει: τῆμος ἄρ᾽ ὑλοτομεῖν μεμνημένος ὥρια ἔργα.

When the piercing power and sultry heat of the sun abate, and almighty Zeus sends the autumn rains, and men's flesh comes to feel far easier,—for then the star Sirius passes over the heads of men, who are born to misery, only a little while by day and takes greater share of night—then, when it showers its leaves to the ground and stops sprouting, the wood you cut with your axe is least liable to worm.

[11] About a century later, Alcaeus repeated the theme, advising his listeners to "steep your lungs in wine" before the arrival of the star since "women are at their foulest but men are weak since they are parched in head and knees".

[23] Pliny's Natural History notes an increase in attacks by dogs during July and August, and advises feeding them chicken manure to curb the tendency.

The 1564 English Hope of Health counseled that purging (bloodletting and induced vomiting) should be avoided during the "Dogge daies" of summer because "the Sunne is in Leo" and "then is nature burnt vp & made weake".

[25] The 1729 British Husbandman's Practice claimed that "The Heat of the Sun is so violent that Men's bodies at Midnight sweat as at Midday: and if they be hurt, they be more sick than at any other time, yea very near Dead".

[1] Sirius observes a period of almost exactly 365¼ days between risings, keeping it largely consistent with the Julian but not the Gregorian calendar; nonetheless, its dates occur somewhat later in the year over a span of millennia.

[34] Many modern sources in the English-speaking world move this still earlier, from July 3 to August 11,[1][34][35][5] ending rather than beginning with or centering on the reappearance of Sirius to the night sky.

For example, London, UK, is slightly farther north than Calgary, Canada, but has a milder climate from the presence of the sea and the warm Gulf Stream current.

A medical institution has reported a connection between Finland's dog days and increased risk of infection in deep surgery wounds,[37][38] although that research remains unverified.

[39] In western literature, apart from the Greek and Roman works mentioned above, the dog days appear in John Webster's 1613 play The Duchess of Malfi,[a] Charles Dickens' 1843 novella A Christmas Carol,[b] R.H. Davis's 1903 short story "The Bar Sinister",[c] J.M.