It is thus evident that all substances from the animal and vegetable kingdom appear to afford more or less nutriment, provided that they contain no elements unlike the animal matter of the being they are intended to nourish. All others are either medicinal or poisonous. Food may be considered nourishing in the ratio of its easy digestion or solution. Magendie attributes the nutritious principle to the greater or lesser proportion of nitrogen or azote. According to his view of the subject, the substances that contain little or no nitrogen are the saccharine and acid fruits, oils, fats, butter, mucilaginous vegetables, refined sugar, starch, gum, vegetable mucus, and vegetable gelatin. The different kinds of corn, rice and potatoes, are elements of the same kind. The azotical aliments, on the contrary, are vegetable albumen, gluten, and those principles which are met with in the seeds, stems and leaves of grasses and herbs, the seeds of leguminous plants, such as peas and beans, and most animal substances, with the exception of fat. To this doctrine, it was objected, that animals who feed upon substances containing little nitrogen, and the field negroes, who consume large quantities of sugar, might be adduced as an exception. Magendie replies, that almost all the vegetables consumed by man and animals contain more or less nitrogen--that this element enters in large quantity in the composition of impure sugar--and lastly, that the nations whose principal food consists in rice, maize, or potatoes, consume at the same time milk and cheese. To support his theory, this physiologist had recourse to various curious experiments on dogs, whom he fed with substances which contained no nitrogen. During the first seven or eight days, the animals were brisk and active, and took their food and drink as usual. In the course of the second week they began to get thin, although their appetite continued good, and they took daily between six and eight ounces of sugar. The emaciation increased during the third week; they became feeble, lost their appetite and activity, and at the same time ulcers appeared in the cornea of their eyes. The animals still continued to eat three or four ounces of sugar daily, but, nevertheless, became at length so feeble as to be incapable of motion, and died on a day varying from the 31st to the 34th: and it must be recollected that dogs will live the same length of time without any food. The same were the results where dogs were fed upon gum, and butter; when they were fed with olive oil and water the phenomena were the same, with the exception of ulceration of the cornea. In Denmark, a diet of bread and water for a month is considered equivalent to the punishment of death. Dr. Stark died in consequence of experiments which he instituted on himself to ascertain the effects of a sugar diet.