Page:Popular Science Monthly Volume 33.djvu/501

Rh to any considerable extent, and if it is practicable to remove or modify them.

We refer chiefly to three, and these are: 1. Disuse of the upper extremities for any considerable muscular exertion. 2. The incessant noise of a large city. 3. Jarring of the brain and spinal cord by continual treading upon the stone and brick pavements which make our sidewalks and streets.

We leave out of the question those to whom these observations do not apply—viz., such as are able to spend nearly half the year out of town. Experience has shown that such individuals and families suffer in small degree from an ordinary city life; while, on the other hand, good authorities assert that there are very few families now living in London who, with their predecessors, have resided there continuously for three generations.

If there is one general physical difference between the country-bred and the city-bred man, it lies in the size and strength of the muscles of the shoulder and arm. It is almost impossible for a man to live in the country without using the arms far more than the average city man. This use of the arms has, in both men and women, an important bearing on the general health, since it increases the capacity of the chest, and thereby the surface of lung tissue where the blood is spread out in thin-walled vessels through which the oxygen and carbonic acid easily pass in opposite directions, serving thus the double purpose of feeding the body more abundantly and of removing a constantly accumulating waste product.

This richer blood is again driven with greater force by increased heart and arterial action through its circuit. The vital organs are better nourished and the power to produce work is increased.

Few will deny that a well-nourished body can be trained to do more and better mental work than the same organism in a feebler state. Walking on an even surface, the only variety of physical exercise which most business and professional men get in town, is well known to be a poor substitute for arm-exertion. The reason is partially plain, since walking is almost automatic and involuntary. The walking mechanism is set in motion as we would turn an hour-glass, and requires little attention, much less volition and separate discharges of force from the brain-surface with each muscular contraction, as is the case with the great majority of arm-movements.

The arm-user is a higher animal than the leg-user. Arm-motions are more nearly associated with mental action than leg movements. A man's lower limbs merely carry his higher centers to his food or work. The latter must be executed with his arms and hands.

A third way in which arm-exercise benefits the organism is