Page:Popular Science Monthly Volume 31.djvu/335

Rh mental labors, anxieties about examinations, all causes that have an influence on growth, there are children whose growth is more accentuated than the mean at some period of their existence; and others, tardy ones, who grow till twenty-five or thirty years old, or even longer. With very many youth, growth does not stop at twenty-one years.

The rate of growth of children varies according to sex. Thus, at the age of eleven and twelve years, boys are larger and heavier than girls; but from that age on the evolution of the girls is more rapid, and they soon overtake the boys and pass them, till the age of fifteen years is reached, when the boys regain the ascendency, while the girls remain nearly stationary. A curious relation has been discovered between the growth of children in stature and in weight. M. Malling-Hansen, Director of the Deaf and Dumb Institution at Copenhagen, has for three years weighed and measured his pupils daily; and he has observed that their growth does not take place regularly and progressively, but by stages separated by intervals of rest. Weight also increases by periods after intervals of equilibrium. While the weight is increasing, the stature remains nearly stationary, and vice versa. The maximum of increase of stature corresponds with a minimum period of augmentation of weight. The vital forces appear not to work on both sides at once. These variations are subject to the influence of the seasons. During autumn and early winter, according to M. Malling-Hansen, the child accumulates weight, while his stature increases slowly; but during spring, stature receives a veritable push, while weight increases but little. Some local habits have an influence on the stature. Stendhal remarked that many Roman girls had deformed vertebral columns, or were a little humpbacked, and found that it was the result of a popular belief prevailing in Rome that parents could promote the growth of their children by punching them in the back! A popular custom in some of the towns of Switzerland also affects the development of the children. Mothers are accustomed to give them brandied lumps of sugar to keep them from crying. It has been learned from experiments on animals that alcohol tends to stunt the growth of the young. The habit of some women of the lower classes of drinking brandy during pregnancy in order to give their children fair complexions must likewise have a bad influence on the development of the children. On the other hand, growth is favored by strong food, rich in nitrogen and phosphates, by good hygiene, by play and gymnastic exercises, by plenty of air, and by all the causes that contribute to make children strong and vigorous.

One of the less recognized agencies affecting stature is fatigue, under the influence of which the height diminishes. A soldier, for instance, is perceptibly taller before than after a forced march; when the body is fatigued it gives way, the cartilages lose their elasticity and become thinner, and the fatty and fibrous cushions, which give