_The Alimentary Canal._—“One of the most interesting comparisons,” says Dr Kellogg,[5] “which has been made by comparative anatomists is the length of the alimentary canal. This is very short in the carnivora, and long in the herbivora. When compared to the length of the body of the different classes of animals, the proportion is found to be as follows:—In the carnivora, the alimentary canal is three times the length of the body; in the herbivora, as the sheep, thirty times the length of the body; in the monkey, twelve times; in the omnivora ten times; in man, as in the frugivora, twelve times. Here, as before, we see that anatomy places man strictly in the frugivorous class. Some writers have made the amusing blunder of making the proportionate length of the alimentary canal in man 1 to 6, instead of 1 to 12, by doubling the height through measuring him while standing erect. This measurement is evidently wrong, for it includes the length of the lower extremities, or hind legs, whereas in other animals the measurement is made from the tip of the nose to the end of the backbone. In omnivorous animals, the alimentary canal is shorter than in the apes and in man, thus affiliating this class more nearly with the carnivora than with the herbivora.
“A curious fact had recently been observed by Kuttner, as related by him in an article published in Virchow’s _Archives_. This author has made extensive anatomical researches respecting the lengths of the small intestine in different classes of persons. He finds that in the vegetarian peasants of Russia, the small intestine measures from twenty to twenty-seven feet in length, while among Germans, who use meat in various forms quite freely, the length of the small intestine varies between seventeen and nineteen feet. The author attributes the difference in these two classes of persons to the difference in diet. Of course differences of this sort must be the influence of the diet exerted through many generations. This observation would seem to suggest that the special anatomical characteristic of the carnivorous class of animals is due to the modifying influence of their diet, acting through thousands of years. If the length of the intestine in man may be shortened by the use of flesh, with other foods, for a few hundred years, more extensive modifications may easily result from the longer experience of animals that subsist upon an exclusively carnivorous diet.”[6]