By comparing records of what he deems standard normal growth with that of 188 naval cadets from sixteen to twenty-one, who had special and systematic training, just after the period of most rapid growth in height, Beyer concluded that the effect of four years of this added a little over an inch of stature, and that this gain as greatest at the beginning. This increase was greatest for the youngest cadets. He found also a marked increase in weight, nearly the same for each year from seventeen to twenty one. This he thought more easily influenced by exercise than height. A high vital index ratio of lung capacity to weight is a very important attribute of good training. Beyer[1] found, however, that the addition of lung area gained by exercise did not keep up with the increase thus caused in muscular substance, and that the vital index always became smaller in those who had gained weight and strength by special physical training. How much gain in weight is desirable beyond the point where the lung capacity increases at an equal rate is unknown. If such measurements were applied to the different gymnastic systems, we might be able to compare their efficiency, which would be a great desideratum in view of the unfortunate rivalry between them. Total strength, too, can be greatly increased. Beyer thinks that from sixteen to twenty-one it may exceed the average or normal increment fivefold, and he adds, "I firmly believe that the now so wonderful performances of most of our strong men are well within the reach of the majority of healthy men, if such performances were a serious enough part of their ambition to make them do the exercises necessary to develop them." Power of the organs to respond to good training by increased strength probably reaches well into middle life.