"I believe I have omitted mentioning that in my first Voyage from Boston, being becalm'd off Block Island, our People set about catching Cod & haul'd up a great many. Hitherto I had stuck to my Resolution of not eating animal Food; and on this Occasion, I consider'd with my Master Tryon, the taking every Fish as a kind of unprovok'd Murder, since none of them had or ever could do us any Injury that might justify the Slaughter. All this seem'd very reasonable. But I had formerly been a great Lover of Fish, & when this came hot out of the Frying Pan, it smeled admirably well. I balanc'd some time between Principle & Inclination: till I recollected, that when the Fish were opened, I saw smaller Fish taken out of their Stomachs: Then thought I, if you eat one another, I don't see why we mayn't eat you. So I din'd upon Cod very heartily and continu'd to eat with other People, returning only now & then occasionally to a vegetable Diet. So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for every thing one has a mind to do."
January 1, 1970
https://en.wikiquote.org/wiki/Vegetarianism