“ The idea of jumping, jerking movement has given rise to many applications of “jig” and its derivative “jigger” to mechanical and other devices, such as the machine used for separating the heavier metal-bearing portions from the lighter parts in ore-dressing, or a tackle consisting of a double and single block and fall, &c. The word “jigger,” a corruption of the West Indian chigoe, is also used as the name of a species of flea, the Sarcopsylla penetrans, which burrows and lays its eggs in the human foot, generally under the toe nails, and causes great swelling and irritation (see Flea) . ”