Volume 1

Health lectures for the people.

Date:
1883-1892
Catalogue details

Licence: Public Domain Mark

Credit: Health lectures for the people. Source: Wellcome Collection.

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    slight it may be, if it be only one of those little breaths of air that we can only feel upon our faces, grateful to us on a hot summer day, or one of those tempests that uproot trees and unroof houses. It is the same thing, differing only in degree. Wind is the air in motion. Now, the truth is that the air is very seldom not in motion. It is exceedingly easily moved, and very slight causes produce motion in the air—not merely any mechanical agent that may make a current of air, but the slightest change in the temperature of the air may set it in motion. I am quite sure you must have observed this yourselves, as at the sea-side, for example, when there is not a breath of wind stirring, as we say, and yet when, if you look out to sea, you may see a dark line upon the surface of the water—I can hardly call it a ripple, it is so very small, but yet it is wind, the air in slow motion, perhaps only because a sunbeam has warmed the surface a little, and led to a current of air by the small change in heat. Now, having said that the wind is air in motion, the next thing that you want to know is—What is air 1 If I put this ques- tion to several of my audience, I should get a variety of answers. Perhaps the first answer I should get from some one is, Oh, the air is what we breathe. And I say true/ and it is essential that we should breathe the air, for if a man, or any other animal, no matter what, is deprived of air, death must follow in the course of a very short while. An animal will perish in little over three minutes if entirely deprived of air. Now, what is the use of air in breathing ? Why do we breathe ? Why do we carry on that work of breathing, of which we are not conscious when we are in health, which we carry on whether we are waking or sleeping, and which everybody knows by practical experience is essential to our continuing to live % Now, I must not be led aside from the immediate object of my lecture to-night, but I wish to point out to you why it is that we require to breathe. It is impossible that any of the parts of our body, any of our bodily organs, can carry on their work unless they are furnished with a full and complete supply of pure blood. Now the blood,