Page:Popular Science Monthly Volume 26.djvu/879

Rh birds were plainly fitted for a predatory life; and the lowest and earliest forma among mammals are decidedly zoöphagous. It may even be permissible to ask if among mammals the purely plant-eating forms have not been developed from a zoöphagous or at least from an omnivorous stock. The only large group which contains no zoophagous or omnivorous members, that of the ruminants, is characterized by its complicated and highly specialized digestive organs, "evidently modified from the normal mammalian type, so as to be adapted to a purely vegetable diet." Numerous animals are zoophagous at one period of their lives and plant-eating at another, and experience a natural and normal change. Thus all mammals begin life as milk-eaters. Likewise all birds begin with a diet of insects and worms or of half-digested food disgorged from the crop of their parents. Changes arising from scarcity of food, or from caprice, are also on record. Domesticated dogs and cats often partake of vegetable matter. Among wild animals the change indict when it occurs is most generally from vegetable to animal. Curiously, when any species has adopted a new diet, it shows a great disinclination to return to its former food. The majority of warm-blooded animals may, however, be regarded as omnivorous, in so far that they consume both animal and vegetable food. Apes and monkeys, generally classed with vegetarians, "never omit an opportunity of robbing a bird's nest, and feed with avidity upon a great variety of insects." The bears and their allies, except the so-called polar bear, carnivores, seem to prefer fruits, roots, honey, insects, and even grain before it is ripened and hardened. "There is no satisfactory evidence that any of the cats in a wild state will consume vegetable matter, but at least two groups of the Canidæ—the foxes and the jackals—are not averse to fruit." Among the rodents an omnivorous character is becoming more and more fully established. The Solidungula, or horse kind, and the ruminants are, so far as is known, strictly vegetarians; but the other sub-order of the Ungulata, that of the pachyderms, includes the swine, the most typically omnivorous animals. Among the birds, the number of purely plant-eating species is relatively smaller, that of the exclusively zoöphagous larger, and that of the forms recognized as omnivorous is increasing as our knowledge of their habits extends. Thus the animal-eating and plant-eating forms of animal life are not separated from each other by any sharply marked characters, but are connected by a multitude of creatures intermediate in their organization, and consequently adapted for a mixed diet.

Health and Density of Population.—Professor de Chaumont recently illustrated the influence of density of population on health, by comparing London and Paris. In Paris every individual had an area of about forty square metres, while in London he had eighty. The result of the difference was clearly shown, not only in the lower death-rate in a larger population, but in the character of the diseases, while some diseases—scarlet fever, for instance—were more severe in London than on the Continent; others, such as typhoid fever and diphtheria, were much more common and fatal in the large cities of the Continent than they were in England. In London, the streets were filthy and the sewers abominable, but the houses were the perfection of cleanliness; whereas, in Paris, one might give a dinner-party in the sewers, and the streets were perfectly clean, but the houses were abominably filthy. In Paris, all the filth was kept in or under the house:-> while in London it was all sent away. The result was shown in the differences in the health of the two cities, particularly in diphtheria, which was described by French sanitarians as the scourge of their country, while in London it took a comparatively low position in the class of zymotic diseases.

Chinese Acupuncture.—The "North China Herald" gives some curious illustrations of the skill of Chinese doctors in cauterization and acupuncture. With two copper coins as his only tools a Mantchoo peasant produced an effectual counter-irritation in a case of slight sunstroke. Acupuncture is performed first in the hollow of the elbow of each arm, and is regarded as successful if blood flows from the wound. If the blood does not appear, the case is regarded as grave, and the operation is repeated in the abdomen, with drawing back and forth of the needle. If the patient shows signs of