After working-hours are over, the girl should make a special effort to sit erect for other reasons than that of breathing, though that is reason enough.
But wrong sitting-postures are not the only attitudes that interfere with deep breathing. Very often the position in standing is also objectionable. When one stands with the weight resting on the heels the body is thrown out of balance, and as a consequence the shoulders are not on a vertical line with the hips. In this attitude it is impossible to manifest fullness of life, because the lungs are not fully inflated with air at each breath. We live, enjoy, accomplish only in proportion to our breathing ability. As one writer says, "The deep thinker, the orator, the fine singer, must of necessity be a good breather."
The most serious hindrance to deep breathing is found in the restrictions of the clothing. I do not say of the corsets, because tight bands or waists can also compress the body and make full breathing impossible. Of course you say your dresses are loose, and you run your hand up under your waist to prove it to me. I will not argue the question with you, but I will ask you to argue it with yourself.
If breathing is the measure of your living and doing, then if, in the least degree, you limit by your dress your breathing, the dress is too tight. "Well," you ask "how shall I know if I am hindering my breathing? My dress feels comfortable. It seems to me that I breathe. Is there any way that I can prove whether my dress is tight or not?"
It is true that one becomes accustomed to uncomfortable things and scarcely realizes that they ever were uncomfortable. The dress may seem a little tight when you first put it on, then it begins to grow comfortable, and after a while it feels loose, and you say it certainly is loose. I will give a simple rule by which you may know whether your clothing is loose enough or not. Unfasten every article of clothing; dress, corset, skirt-bands, everything. Now breathe in slowly until every air-cell is full. It may take some practice to do this, but persevere until you find the chest elevated and filled to its utmost extent. It should swell out at the sides along the line of the insertion of the diaphragm. There should be no heaving of the chest. Now, with the lungs so completely filled with air, bring your dress waist together without pulling a particle. Will it fasten without pressing out a bit of air from the lungs? If so, it is loose enough. If, however, you have to pull it together, even to the tiniest extent, you have pressed out some of the air. The minute air-cells that have thus been emptied cannot be again filled while the dress is fastened. Therefore you are defrauded of your rightful amount of air, and because part of the air is pressed out, the lungs take less space and the dress seems looser. You can understand how that would be.
The trouble is that our dresses are usually fitted over empty lungs. The dressmaker pulls the dress together, squeezes the air out of the lungs, and fastens the dress. Now you can readily understand that it will be impossible to fill those air-cells so long as the dress is worn, and yet it may not seem uncomfortable, because we become accustomed to it. Nature has made us so that we can accustom ourselves to many things that are not absolutely healthful, but this should not make us willing to live unhealthfully when it is possible to avoid it.