The musk bag cut by the hunter from the body of the animal has the size and shape of half a walnut. On the side by which it was attached to the body of the animal it is membranous and nearly smooth; on the external surface it is more or less hemispherical and covered with light brown or dark brown hair, according to the season at which the animal was killed. The hair assumes a circular arrangement around an opening situated in the centre of the bag. This opening, the efferent duct of the gland, is formed by a ring-shaped muscle which yields to the pressure of a pointed object and permits the introduction of the point of the finger. Internally the musk bag consists of several layers of membrane which surround the musk itself. It is probable that the musk is secreted by these membranes, for when the animal is dissected, no direct communication of the musk gland with the body can be detected. It has been surmised that the secretion of musk bears some relation to the food; at least it has been asserted that the animals eat, among other things, sumbul root with great avidity; and this root, it will be remembered, has a very intense odor of musk. However, though this appears probable at first sight, it is contradicted by the fact that the females and the young males likewise eat the root without manifesting any odor of musk nor do they secrete the substance, while the older males produce it even when they are fed with hay only. Another fact is of interest, namely, that other ruminants, too, for instance, cattle, diffuse a marked though faint odor of musk which occurs also in their excrements, exactly as in the case of the musk deer. Alligators likewise produce a musk-like substance which has actually been made use of in place of musk for coarser purposes. The musk present in the glands differs in appearance with the season and the age of the animal. Musk deers killed in spring have in their musk bag an unctuous soft mass of a reddish-brown color with the strongest odor; at other seasons the mass is darker in color, almost black, and granular; the size of the grains ranges from that of a millet-seed to that of a large pea. That the secretion of musk belongs to the sexual functions appears probable from the fact that it can be found only in the bags of males more than two years old; that of younger animals contains only a substance of a milky consistence, whose odor has no resemblance to that of musk. The quantity of musk present in a bag varies with the season and the age of the animal; the smallest quantity may be assumed at about six drachms, though some bags contain as much as one and a half ounces.