place whatever in the religionism or pseudo-philosophy of the whole of the ages distinguished as the _Mediæval_--that is to say, from about the fifth or sixth to the sixteenth century--and, in fact, there existed not only a negative indifferentism, but even a positive tendency towards the still further depreciation and debasement of the extra-human races, of which the great doctor of mediæval theology, St. Thomas Aquinas (in his famous _Summa Totius Theologiæ_--the standard text book of the orthodox church), is especially the exponent. After the revival of reason and learning in the sixteenth century, to Montaigne, who, following Plutarch and Porphyry, reasserted the rights of the non-human species in general; and to Gassendi, who reasserted the right of innocent beings to life, in particular, among philosophers, belongs the supreme merit of being the first to dispel the long-dominant prejudices, ignorance, and selfishness of the common-place teachers of Morals and Religion. For orthodox Protestantism, in spite of its high-sounding name, so far at least as its theology is concerned, has done little in _protesting_ against the infringement of the moral rights of the most helpless and the most harmless of all the members of the great commonwealth of Living Beings. The principles of Dietary Reform are widely and deeply founded upon the teaching of (1) Comparative Anatomy and Physiology; (2) Humaneness, in the two-fold meaning of Refinement of Living, and of what is commonly called “Humanity;” (3) National Economy; (4) Social Reform; (5) Domestic and Individual Economy; (6) Hygienic Philosophy, all of which are amply displayed in the following pages. Various minds are variously affected by the same arguments, and the force of each separate one will appear to be of different weight according to the special bias of the inquirer. The _accumulated_ weight of all, for those who are able to form a calm and impartial judgment, cannot but cause the subject to appear one which demands and requires the most serious attention. To the present writer, the humanitarian argument appears to be of double weight; for it is founded upon the irrefragable principles of Justice and Compassion--universal Justice and universal Compassion--the two principles most essential in any system of ethics worthy of the name. That this argument seems to have so limited an influence--even with persons otherwise humanely disposed, and of finer feeling in respect to their own, and, also, in a general way, to other species--can be attributed only to the deadening power of custom and habit, of traditional prejudice, and educational bias. If they could be brought to reflect upon the simple ethics of the question, divesting their minds of these distorting media, it must appear in a light very different from that in which they accustom themselves to consider it. This subject, however, has been abundantly insisted upon with eloquence