Dog-days

Dog-days (Dies Caniculares) is a name given by the ancient astronomers to the 20 days before and 20 days after the rising of the Dog-star or Sirius (q.v.), at present reckoned from 3d July to 11th August. It is a mere accident that the rising of Sirius falls in the hottest season of the northern year; in time it will be in the dead of winter. But the ancients attributed the heat and the accompanying diseases directly to the influence of the star—as also in Egypt the highest rising of the Nile.