From these facts we may deduce certain very important principles that throw useful light upon pedagogy: there are certain ages at which even the strong are weak; and their weakness is of such a nature that it exposes the individual to death.

Now, whenever the phenomenon of mortality occurs it is always an indication of impoverishment in the survivors. For example, of every one person that dies, many persons have been ill who have recovered from their illness; but there are still many others who, although they did not actually fall ill, were weakened even though they passed through the peril unharmed.

In short, for each death, which represents a final disaster, there are many victims. And whenever there is a rise in the phenomenon of mortality in connection with any one age, it is our duty to give special attention to those individuals who are not only weak in themselves, but whom the social causes affecting them tend to weaken still more and push onward toward illness and death. Whenever there are many deaths, there are undoubtedly also many sufferers.

Now, in pedagogy we have no criterion to guide us in this matter of respecting the weaknesses characteristic of the various ages, as, for example, that of early infancy and of the age of puberty.

With the most cruel blindness we punish and discourage the lad who, having reached the age of puberty, no longer makes the progress in his studies that rendered him the brilliant champion during the period of physiological repose in his growth; and instead of regarding this as a psychic indication of a great physiological transformation that it is necessary to protect, we urge on the organism to enforced effort, without even suspecting that, in proportion to the degree of resistance of our pupil, we may be doing our share to induce in him a permanent weakness, or an arrest of development, or disease and death.

Our responsibility as educators is great, because we have the threads of life entrusted to our care; man represents a continuous transition through successive forms, and each following period has been prepared for by the one preceding.

Whenever we have the misfortune to concur in weakening a child, we touch that parabolic line traced in the graphic chart of stature, and standing as an index of the life of the body, and we give it a shock throughout its whole length; it may either be shattered or be brought down to a lower grade.

But the life of an individual does not contain merely that individual alone; the cycle of the stature with its violent period of puberty and the perfect physiological repose corresponding to the years from 25 to 36, or even 45, indicates the eternity of the individual in the species: his maturity for reproduction. Man in his progress through the different levels of height, as indicated on the graphic chart of stature, does not pass through them without reproducing himself, save in exceptional cases; he commences the ascent alone, but in his descent he attains the majesty of a creator who leaves behind him the immortal works of his own creation. Well, even the capacity of normal reproduction, and of begetting a strong species, is related to the normal cycle of life: whoever weakens a child and puts a strain upon the threads of its existence, starts a vibration that will be felt throughout posterity.