"Sotion used to tell me why Pythagoras abstained from animal food, and why, in later times, Sextius did also. In each case, the reason was different, but it was in each case a noble reason. Sextius believed that man had enough sustenance without resorting to blood, and that a habit of cruelty is formed whenever butchery is practised for pleasure. Moreover, he thought we should curtail the sources of our luxury; he argued that a varied diet was contrary to the laws of health, and was unsuited to our constitutions. Pythagoras, on the other hand, held that all beings were inter-related, and that there was a system of exchange between souls which transmigrated from one bodily shape into another."