After the extinction of Greek and Latin philosophy in the fifth century, a mental torpor seized upon and, during some thousand years, with rare exceptions, dominated the whole Western world. When this torpor was dispelled by the influence of returning knowledge and reason evoked by the various simultaneous discoveries in science and literature--in particular by the achievements of Gutenberg, Vasco da Gama, Christopher Colon, and, above all, Copernik--the moral sense then first, too, began to show signs of life. The renascence of the sixteenth century, however, with all the vigour of thought and action which accompanied it, proved to be rather a revival of mere verbal learning than of the higher moral feeling of the best minds of old Greece and Italy. Men, fettered as they were in the trammels of theological controversy and metaphysical subtleties, for the most part expended their energies and their intellect in the vain pursuit of phantoms. With the very few splendid exceptions of the more enlightened and earnest thinkers, _Ethics_, in the real and comprehensive meaning of the word, was an unknown science; and a long period of time was yet to pass away before a perception of the universal obligations of Justice and of Right dawned upon the minds of men. In truth, it could not have been otherwise. Before the moral instincts can be developed, reason and knowledge must have sufficiently prepared the way. When attention to the importance of the neglected science of _Dietetics_ had been in some degree aroused, the interest evoked was little connected with the higher sentiments of humanity. Of all dietary reformers who have treated the subject from an exclusively sanitarian point of view, the most widely known and most popular name, perhaps, has been that of Luigi Cornaro; and it is as a vehement protester against the follies, rather than against the barbarism, of the prevailing dietetic habits that he claims a place in this work. He belonged to one of the leading families of Venice, then at the height of its political power. Even in an age and in a city noted for luxuriousness and grossness of living of the rich and dominant classes, he had in his youth distinguished himself by his licentious habits in eating and drinking, as well as by other excesses. His constitution had been so impaired, and he had brought upon himself so many disorders by this course of living, that existence became a burden to him. He informs us that from his thirty-fifth to his fortieth year he passed his nights and days in continuous suffering. Every sort of known remedy was exhausted before his new medical adviser, superior to the prejudices of his profession and of the public, had the courage and the good sense to prescribe a total change of diet. At first Cornaro found his enforced regimen almost intolerable, and, as he tells us, he occasionally relapsed.