The following diagram indicates the progressive evolution and involution of the ponderal index throughout the successive stages of life:
The ponderal index has revealed certain physiological conditions in pupils that are extremely interesting. Some authors had already noted that the ponderal index was higher in well-nourished children (Binet, Niceforo, Montessori); but last year one of my own students, Signorina Massa, in a noteworthy study of children, all taken from the same social class and quite poor, and who did not attend the school refectory or have the advantage of any other physiological assistance, established the fact that the more studious children, the prize winners, have a lower ponderal index and a muscular force inferior to that of the non-studious (negligent) pupils. That the development of the ponderal index stands in some relation to the muscular force, might already have been deduced from the fact that the greatest increase of weight is due, in the evolution of the individual, to the system of striped muscles. Studious children, accordingly, are sufferers from denutrition through cerebral consumption; furthermore, they are weakened throughout their whole organism; in fact, I discovered, in the course of researches made among the pupils in the elementary schools of Rome, that the studious children, those who received prizes, had a scantier chest measurement than the non-studious. This goes to prove that school prizes are given at the cost of a useless holocaust of the physiological forces of the younger generations!
That the ponderal index has an eminently physiological significance, is further shown by the following comparative figures between normal and weak-minded children. The stature, which is biologically significant, is lower in the weak-minded; but their ponderal index is greater when they are well fed, as in the asylums in Paris.
Accordingly, the sole cause of the physical inferiority of studious children is study, cerebral fatigue.
BIO-PHYSIOLOGICAL DIFFERENCES BETWEEN NORMAL AND WEAK-MINDED CHILDREN
(Simon and Montessori: Based on Children from 9 to 11)
| Age | Weight in kilograms | Average stature | Ponderal index | |||
|---|---|---|---|---|---|---|
| Weak-minded | Normal | Weak-minded | Normal | Weak-minded | Normal | |
| 9 | 21.0 | 25.5 | 1.15 | 1.24 | 24 | 23.9 |
| 10 | 26.5 | 28.5 | 1.25 | 1.30 | 24 | 23.6 |
| 11 | 27.0 | 30.5 | 1.25 | 1.33 | 24 | 23.6 |
It should be noted that in the foregoing table the normal children include both the studious and the non-studious.
FOOTNOTES:
[4] See further, as to these fundamental ideas: Laloy, L'Évolution de la Vie. Petite Encyclopédie du XX Siècle; Claude Bernard, Leçons sur les Phènomènes de la Vie; Le Dentu, in La Matière Vivante, et Théorie nouvelle de la Vie; Luciani, Fisiologia Umana, in the first chapter: "Material Substratum of Vital Phenomena."