This is the oldest of many expressions that use the word whole to mean completely, all the way or the whole lot. Go the whole hog dates from the early 19th century and has even been turned into jocular, fake Latin, totus porcus. The origin of the expression remains obscure but some etymologists attribute the origin to William Cowper in his book The Love of the World: Hypocrisy Detected (1779). According to Cowper, some Muslim divines believed that the prophet Mohammed had not forbidden the eating of pork but only one particular part of the animal. Muslim holy men, however, could not agree on what that part was and Cowper observed that it was lamentable that Muslims should be denied the ‘whole hog’ for one particular piece. Another theory is that it has to do with butchery in that it is cheaper to buy a whole pig rather than parts of it. This theory seems weak because the same could apply to any animal, the whole sheep, the whole cow etc. The William Cowper origin is also dubious because the expression is first cited over one hundred years after he is supposed to have coined it.