Prometheus (who represents the human race) effected some great change in the condition of his nature, and applied fire to culinary purposes; thus inventing an expedient for screening from his disgust the horrors of the shambles. From this moment his vitals were devoured by the vulture of disease. It consumed his being in every shape of its loathsome and infinite variety, inducing the soul-quelling sinkings of premature and violent death. All vice arose from the ruin of healthful innocence. Tyranny, superstition, commerce, and inequality, were then first known, when reason vainly attempted to guide the wanderings of exacerbated passion. […]

Man, and the animals whom he has infected with his society, or depraved by his dominion, are alone diseased. The wild hog, the mouflon, the bison, and the wolf, are perfectly exempt from malady, and invariably die either from external violence, or natural old age. But the domestic hog, the sheep, the cow, and the dog, are subject to an incredible variety of distempers; and, like the corrupters of their nature, have physicians who thrive upon their miseries. The supereminence of man is like Satan’s, a supereminence of pain; and the majority of his species, doomed to penury, disease and crime, have reason to curse the untoward event, that by enabling him to communicate his sensations, raised him above the level of his fellow animals. But the steps that have been taken are irrevocable. The whole of human science is comprised in one question:—How can the advantages of intellect and civilization be reconciled with the liberty and pure pleasures of natural life? How can we take the benefits, and reject the evils of the system, which is now interwoven with all the fibres of our being?—I believe that abstinence from animal food and spirituous liquors would in a great measure capacitate us for the solution of this important question.

It is true, that mental and bodily derangement is attributable in part to other deviations from rectitude and nature than those which concern diet. The mistakes cherished by society respecting the connection of the sexes, whence the misery and diseases of unsatisfied celibacy, unenjoying prostitution, and the premature arrival of puberty necessarily spring; the putrid atmosphere of crowded cities; the exhalations of chemical processes; the muffling of our bodies in superfluous apparel; the absurd treatment of infants:—all these, and innumerable other causes, contribute their mite to the mass of human evil.

Comparative anatomy teaches us that man resembles frugivorous animals in everything, and carnivorous in nothing; he has neither claws wherewith to seize his prey, nor distinct and pointed teeth to tear the living fibre. A Mandarin of the first class, with nails two inches long, would probably find them alone inefficient to hold even a hare. After every subterfuge of gluttony, the bull must be degraded into the ox, and the ram into the wether, by an unnatural and inhuman operation, that the flaccid fibre may offer a fainter resistance to rebellious nature. It is only by softening and disguising dead flesh by culinary preparation, that it is rendered susceptible of mastication or digestion; and that the sight of its bloody juices and raw horror does not excite intolerable loathing and disgust. Let the advocate of animal food force himself to a decisive experiment on its fitness, and, as Plutarch recommends, tear a living lamb with his teeth, and plunging his head into its vitals, slake his thirst with the steaming blood; when fresh from the deed of horror, let him revert to the irresistible instincts of nature that would rise in judgment against it, and say, Nature formed me for such work as this. Then, and then only, would he be consistent. […]

[The passage omitted details the resemblances between human anatomy and that of herbivorous animals and remarks on the use of animal food and alcoholic beverages as acquired habits; when these are overcome, bodily and mental well-being naturally follow.]

What is the cause of morbid action in the animal system? Not the air we breathe, for our fellow denizens of nature breathe the same uninjured; not the water we drink, (if remote from the pollutions of man and his inventions),* for the animals drink it too; not the earth we tread upon; not the unobscured sight of glorious nature, in the wood, the field, or the expanse of sky and ocean; nothing that we are or do in common with the undiseased inhabitants of the forest. Something then wherein we differ from them: our habit of altering our food by fire, so that our appetite is no longer a just criterion for the fitness of its gratification. Except in children, there remain no traces of that instinct which determines, in all other animals, what aliment is natural or otherwise; and so perfectly obliterated are they in the reasoning adults of our species, that it has become necessary to urge considerations drawn from comparative anatomy to prove that we are naturally frugivorous.

Crime is madness. Madness is disease. Whenever the cause of disease shall be discovered, the root, from which all vice and misery have so long overshadowed the globe, will lie bare to the axe. All the exertions of man, from that moment, may be considered as tending to the clear profit of his species. No sane mind in a sane body resolves upon a real crime. It is a man of violent passions, blood-shot eyes, and swollen veins, that alone can grasp the knife of murder. The system of a simple diet promises no Utopian advantages. It is no mere reform of legislation, whilst the furious passions and evil propensities of the human heart, in which it had its origin, are still unassuaged. It strikes at the root of all evil, and is an experiment which may be tried with success, not alone by nations, but by small societies, families, and even individuals. In no cases has a return to vegetable diet produced the slightest injury; in most it has been attended with changes undeniably beneficial. Should ever a physician be born with the genius of Locke, I am persuaded that he might trace all bodily and mental derangements to our unnatural habits, as clearly as that philosopher has traced all knowledge to sensation.