Page:Popular Science Monthly Volume 21.djvu/499

Rh exist when the ratio of brain to body is examined in different animals. Thus in man, as is the. case with lower animals, the ratio diminishes with increasing weight and height. In lean persons the ratio is often as 1: 22 to 27, and in stout persons as 1: 50 to 100. In the Greenland whale the ratio is given as 1 to 3,000; in the ox as 1 to 160; in the horse as 1 to 400; in the dog as 1 to 305; in the elephant as 1 to 500; in the chimpanzee as 1 to 50; and in man as 1 to 36.

The absolute weight of brain in an elephant which was seven and a half feet high, and eight and a half feet in length from forehead to tail, was nine pounds. The brain of an Indian elephant was found to weigh ten pounds; and Sir Astley Cooper gives the weight of the brain of another specimen as eight pounds, one ounce, and two grains; while that of an African elephant seventeen years old was found by Perrault to weigh nine pounds.

The muscular system of the elephant necessarily partakes of the massive character adapted for the work of moving and transporting the huge frame. But the anatomy of the "proboscis" or "trunk" constitutes in itself a special topic of interest, and one, moreover, which gives to the proboscidian race one of its most notable characteristics. The "trunk" is, of course, the elongated nose of the elephant. It is perforated by the nostrils which open at its tip, and above the apertures is a curious finger-like process, which, when opposed to a small projection somewhat resembling a thumb in function, constitutes a veritable hand, and is utilized by the animal in almost every detail of its life. With the exception cf the snout of the tapirs, the trunk of the elephant has not even a distant parallel in the animal series. Its muscles form two sets of fibers, one set of which compressing its substance also extends its length, while the second set shortens the organ and enables it to bend freely in any direction. When we add to the possession of this extreme muscularity a high degree of sensitiveness, the proboscis of these animals may be regarded in the light of one of the most useful as well as most interesting features of their organization. Its use is not limited to the prehension of food (Fig. 2, 1, 2), however, or even to the additional function of an organ of touch. Occasionally, water is drawn up into the trunk, and is then squirted over the body as from a flexible hose (Fig. 2, 3), thus serving as a kind of shower-bath apparatus; and stories have been recorded wherein such a use of the proboscis has played a prominent part in the act of elephantine revenge on some over-bold or offending human.

The teeth of the elephantine race form a highly characteristic feature of their anatomy. In the mouth of a higher quadruped, such as man, the bat, or ape, no less than four kinds of teeth are represented. These are the front teeth, or incisors, the "eye-teeth," or canines, the premolars, and the molars, or "grinders."

In the elephants, only two kinds of teeth are represented, these