16 What say you, O you—! Is that foul smell, then, which is given forth and emitted by burning hides, by bones, by bristles, by the fleeces of lambs, and the feathers of fowls— is that a favour and an honour to the deity? And are the deities honoured by this, to whose temples, when you arrange to go, you come cleansed from all pollution, washed, and perfectly pure? And what can be more polluted than these, more unhappy, more debased, than if their senses are naturally such that they are fond of what is so cruel, and take delight in foul smells which, when inhaled with the breath, even those who sacrifice cannot bear, and certainly not a delicate nose?
But if you think that the gods of heaven de honoured by the blood of living creatures being offered to them, why do you not sacrifice to them both mules, and elephants, and asses? Why not dogs also, bears, and foxes, camels, and hyaenas, and lions? And as birds also are counted victims by you, why do you not sacrifice vultures, eagles, storks, falcons, hawks, ravens, sparrow-hawks, owls, and, along with them, salamanders, water-snakes, vipers, tarantulae? For indeed there is both blood in these, and they are in like manner moved by the breath of life.
What is there more artistic in the former kind of sacrifices, or less ingenious in the latter, that these do not add to and increase the grandeur of the gods? Because, says my opponent, it is right to honour the gods of heaven with those things by which we are ourselves nourished and sustained, and live; which also they have, in their divine benevolence, deigned to give to us for food. But the same gods have given to you both cumin, cress, turnips, onions, parsley, esculent thistles, radishes, gourds, rue, mint, basil, flea-bane, and chives, and commanded them to be used by you as part of your food; why, then, do you not put these too upon the altars, and scatter wild-marjoram, with which oxen are fed, over them all, and mix among them onions with their pungent flavour?
Source: Against the Heathen (New Advent)