Sudoriferous glands: In the middle of each of the transverse furrows between the papillæ, and irregularly scattered between the bases of the papillæ in those parts of the surface of the body in which there are no furrows between them, are the orifices or ducts of the sudoriferous, or sweat glands, by which it is probable that a large portion of the aqueous and gaseous materials excreted by the skin are separated. Each of these glands consists of a small lobular mass, which appears formed of a coil of tubular gland-duct surrounded by blood-vessels and imbedded in the subcutaneous adipose tissue. From this mass the duct ascends, for a short distance, in a spiral manner through the deeper parts of the cutis, then passing straight, and then sometimes again becoming spiral, it runs through the cuticle and opens by an oblique, valve-like apparatus. The sudoriferous glands are abundantly distributed over the whole surface of the body; but are especially numerous, as well as very large, in the skin of the palm of the hand. They are estimated from 2,738 to 3,528 in each superficial square inch. They are almost equally abundant and large in the skin of the sole. The glands by which the peculiar odorous matter of the axilla is secreted form a nearly complete layer under the cutis, and are like the ordinary sudoriferous glands, except in being larger and having very short ducts. In the neck and back, where they are least numerous, the glands amount to 417 on the square inch. The total number is estimated, at 2,381,248; and supposing the orifice of each gland to present a surface of 1/54 of a line in diameter (and regarding a line as equal to 1/10 of an inch) the whole of the glands would present an evaporating surface of about eight square inches. Sebaceous glands secrete a peculiar fatty matter. Like the sudoriferous glands, they are abundantly distributed over most parts of the body. The quantity of matter which leaves the human body by way of the skin is very considerable. It is estimated that while 7 grains pass through the lungs per minute, as much as 11 escape through the skin. The amount varies extremely. It is calculated that the total amount of perspiration excreted from the whole body in 24 hours might range from 2 to 20 kilos. The total amount of perspiration is affected not only by the condition of the atmosphere, but also by the nature and quantity of food taken, the amount of fluid drunk, and the amount of exercise taken. It is also influenced by the mental condition, by medicines and poisons, by disease, and by the relative activity of the other excreting organs, more particularly the kidneys.