As a rule during the fourth month, and often during the third month,
the head can be held erect when the body is supported.

_When does an infant first laugh aloud?_

Usually from the third to the fifth month.

_When does it begin to reach for toys and handle them?_

Usually from the fifth to the seventh month.

_At what age should a child be able to sit and to stand alone?_

At seven or eight months a healthy child is usually able to sit erect
and support the body. During the ninth and tenth months are usually
seen the first attempts to bear the weight upon the feet, and at
eleven or twelve months most children can stand with assistance.

_When should a child walk alone?_

The first attempts are generally seen in the twelfth or thirteenth
month. At fifteen or sixteen months the average child is able to run
alone.

_What conditions postpone these events?_

Prematurity, a very delicate constitution, any severe or prolonged
illness, and especially chronic disturbances of digestion making
feeding difficult. A common cause of late sitting, standing, or