If there is the slightest trouble with the action of the heart or the breathing, then all of the exercises must be taken with much more moderation until the symptoms disappear. Even the worst of heart and lung troubles will either vanish, or will be greatly mitigated, if jiu-jitsu is persistently followed and with the moderation and lightness of strain that must be determined by the student's own intelligence, his physician, or his physical trainer.
Good nature enters into this work as a factor of prime importance. Without it there cannot be the highest development of good health. Anger is a poisonous irritant of the heart. It upsets the nerves. An examination of the Japanese vital statistics will show that heart disease and nervous prostration are almost unknown as causes of death. Moderation in exercise, with all the other forms of right living indicated by the Japanese system, will make a reasonably strong man of one who has become something of a physical and nervous wreck. But absolute good nature is the only tonic of value that can be found at Nature's drug-store. Twenty-five hundred years of training in jiu-
