The solids would consist of the elements oxygen, hydrogen, carbon, nitrogen, phosphorus, sulphur, silicon, chlorine, fluorine, potassium, sodium, calcium (lithium), magnesium, iron (manganese, copper, lead), and may be arranged under the heads of—

Proteids. Amyloids. Fats. Minerals.

Such a body would lose in 24 hours-of water, about 40,000 grains, or 6 lbs.; of other matters about 14,500 grains, or over 2 lbs. ; among which of carbon 4,000 grains; of nitrogen 300 grains; of mineral matters 400 grains; and would part, per diem, with as much heat as would raise 8,700 lbs. of water from 0° to 1° Fahr., which is equivalent to 3,000 foot-tons.1 Such a body ought to do as much work as is equal to 450 foot-tons.

The losses would occur through various organs, thus-by

Lungs

WATER. OTHER MATTER. N

C.

Skin

10,000

Fæces

2,000

800 40

460

Total. . 40,000 14,500 300 4,000

The gains and losses of the body would be as follows::

1 A foot-ton is the equivalent of the work required to

lift one ton one foot high.

Such a body would require for daily food, carbon 4,000 grains; nitrogen 300 grains, which, with the other necessary elements, would be most conveniently disposed in

which, in turn, might be obtained, for instance, by

The fæces passed, per diem, would amount to about 2,800 grains, containing solid matter, 800 grains.

III. CIRCULATION.

In such a body, the heart would beat 75 times a minute, and probably drive out, at each stroke from each ventricle, from 5 to 6 cubic inches, or about 1,500 grains of blood.

The blood would probably move in the great arteries at a rate of about 12 inches in a second, in the capillaries at 1 to 1 inches in a minute; and the time taken up in performing the entire circuit would probably be about 30 seconds.

The left ventricle would probably exert a pressure on the aorta equal to the pressure on the square inch of a column of blood about 9 feet in height; or of a column of mercury about 9 inches in height; and would do in 24 hours an amount of work equivalent to about 90 foot-tons; the work of the whole heart being about 120 foot-tons.

IV. RESPIRATION.

Such a body would breathe 15 times a minute. The lungs would contain of residual air about 100 cubic inches, of supplemental or reserve air about 100 cubic inches, of tidal air 20 to 30 cubic inches, and of complemental air 100 cubic inches.

The vital capacity of the chest, that is, the greatest quantity of air which could be inspired or expired, would be about 230 cubic inches.

There would pass through the lungs, per diem, about 350 cubic feet of air.

In passing through the lungs, the air would lose from 4 to 6 per cent. of its volume of oxygen, and gain 4 to 5 per cent. of carbonic acid.

During 24 hours there would be consumed about

10,000 grains oxygen; and produced about 12,000 grains carbonic acid, corresponding to 3,300 grains carbon. During the same time about 5,000 grains or 9 oz. of water would be exhaled by the lungs.

In 24 hours such a body would vitiate 1750 cubic feet of pure air to the extent of 1 per cent. or 17,500 cubic feet of pure air to the extent of 1 per 1,000. Taking the amount of carbonic acid in the atmosphere at 3 parts, and in expired air at 470 parts in 10,000, such a body would require a supply per diem of more than 23,000 cubic feet of ordinary air, in order that the surrounding atmosphere might not contain more than 1 per 1,000 of carbonic acid (when air is vitiated from animal sources with carbonic acid to more than 1 per 1,000, the concomitant impurities become appreciable to the nose). A man of the weight mentioned (11 stone) ought, therefore, to have at least 800 cubic feet of well ventilated space.

V. CUTANEOUS EXCRETION.

Such a body would throw off by the skin-of water about 18 ounces, or 10,000 grains; of solid matters about 300 grains; of carbonic acid about 400 grains, in 24 hours.

VI. RENAL EXCRETION.

Such a body would pass by the kidneys-of water about 50 ounces; of urea about 500 grains; of other solid matters about 500 grains, in 24 hours

VII. NERVOUS ACTION.

In the frog a nervous impulse travels at the rate of about 80 feet in a second.

In man a nervous (sensory) impulse has been variously calculated to travel at 100, 200, or 300 feet in a second.

VIII. HISTOLOGY.

Red corpuscles of the blood are about 3200th of an inch in breadth; white corpuscles 20th.

Striated muscular fibres are about th of an inch in breadth; plain oth.

Nerve-fibres vary between both and 12000th of an inch in breadth.

Connective tissue fibrils are about booth of an inch in breadth.

Epithelium scales (of the skin) are about th of an inch in breadth.

Capillary blood-vessels are from both to both of an inch in breadth.

Cilia (from the wind-pipe) are about 3000th of an inch in length.

The cones in the "yellow spot" of the retina are about 1ooooth of an inch in breadth.