As to the customs observed at menstruation by Indian women in South America, see further A. d'Orbigny, L'Homme Americain (Paris, 1839), i. 237.

It exerts the greatest influence upon the time of eruption of the teeth, both the temporary and the permanent, the onset of puberty, the recurrence of menstruation in women, and the time of occurrence of labor.

The earlier puberty and menstruation of the warmer climates may be explained as due to an earlier regression of the pineal under the pressure of a great amount of light playing upon the skin.

In Yap, one of the Caroline Islands, should a girl be overtaken by her first menstruation on the public road, she may not sit down on the earth, but must beg for a coco-nut shell to put under her.