A DIFFERENCE IN THE METABOLISM OF THE SEXES 33
of high altitudes. More boys are born in the country than in cities, because city diet is richer, especially in meat ; Busing shows that in Prussia the numerical excess of boys is greatest in the country districts, less in the villages, still less in the cities, and least in Berlin. 1 In times of war, famine, and migration more boys are born, and more are born also in poor than in well-to-do families. European statistics show that when food stuffs are high or scarce the number of marriages diminishes, and in con- sequence a diminished number of births follows, and a height- ened per cent, of boys; with the recurrence of prosperity and- an increased number of marriages and births, the per cent, of female births rises (though it never equals numerically that of the males) . a More children are born from warm-weather than from cold-weather conceptions, 3 but relatively more boys are born from cold-weather conceptions. Professor Axel Key has shown from statistics of 18,000 Swedish school children that from the end of November and the beginning of December until the end of March or the middle of April, growth in children is feeble. From July-August to November-Decem- ber their daily increase in weight is three times as great as dur- ing the winter months. 4 This is evidence in confirmation of a connection between maleness, slow growth, and either poor nutri- tion or cold weather, or both. Physical growth is also completed earlier by girls than by boys, and girls from the well-nourished classes reach puberty at an earlier age than girls from the poor classes. Professor Key's investigations 5 have also confirmed the well-known fact that maturity is reached earlier in girls than in boys, and have shown that in respect of growth the ill-nour- ished girls follow the law of growth of the boys. Growth is a function of nutrition, and puberty is a sign that somatic growth
'DOSING, Geburten in Preussen, pp. 29-33.
- Geburten in Preussen, pp. 14-19.
II. I'LOSS, Das Weib in der ffatur- tnid Volkerkunde, 3. Aufl., Vol. I, p. 419.
- AXEL KEY, "Die rulcrtatsentwickelung und das Vcrhaltn. .Icrselbcn zu den
Krankheitserecheinungen dcr Schuljugend," Verhandlungen des -V. International** Medicinixchen Congresses, 1890, \ '<>!. I. p. 91.
s Ibid., pp. 84-90.
