Note (return) — ORGANIC DIFFERENCES IN THE SEXES

Some facts in the brain development of women point to the same conclusion. The growth of the brain is relatively more rapid in women than in men before the twentieth year. Between 15 and 20 it has reached its maximum, and from that time there is a gradual decline in weight until about the fiftieth year, when there is an acceleration of growth, followed by a renewed diminution after the sixtieth year. The maximum of brain weight is almost reached by men at 20 years, but there is a slow increase until 30 or 35 years. There is then a diminution until the fiftieth year, followed by an acceleration, and at 60 years again a rapid diminution in weight; but the acceleration is more marked and the final diminution less marked in woman than in man.93 A table prepared by Topinard shows that woman from 20 to 60 years of age has from 126 to 164 grams less brain weight than man, while her deficit from 60 to 90 years is from 123 to 158 grams.94