A
drudge,
factotum, general
menial, or
gofer. Also written as dog's body, dog's-body, and dogs-body.
Originally naval slang. It first meant a kind of general-purpose food: dried pease boiled in a cloth, or later "sea-biscuits soaked into a pulp with water and sugar".
This was transferred to junior officers, in particular a junior midshipman. The first known written occurrence of the personal sense "drudge" is in a 1922 letter of T.E. Lawrence.