After about three weeks the individual should be again measured, by the same person, in exactly the same way, in order to learn whether there has been development or not, and, if so, how much. It is important that the measurements should be made at exactly the same horizontal planes, and with this end in view it is desirable to put a small mark of some kind on the chest, which may remain till the next measurements are made.
The method of breathing recommended is as follows:
1. Inhale very slowly through the nostrils, with closed mouth, counting mentally one, two, three, four, etc., with regularity.
2. Hold the breath thus taken, but only for a short time, counting in the same manner as before.
3. Exhale slowly, still counting.
After a few moments' rest the exercise may be again carried out in the same way. These exercises may be in series, several times a day.
The following warnings are especially to be observed:
1. Never continue any exercise when there is a sense of discomfort of any kind whatever. Such usually indicates that it is being carried out too vigorously.
2. Increase the depth of the inspirations daily, but not very rapidly.
3. The inspirations and expirations should both be carried out very slowly at first.