The development of a group of healthy babies under medical supervision was observed at frequent intervals, particular attention being given to the feeding abilities and feeding reactions of each infant. These are admirably illustrated by studies made with a moving picture camera. Many of the findings are of interest. For example, the infant in the first month, if left to himself, will nurse at the breast thirty to forty minutes. As he grows older he will reduce this time one-half. Refusal of food should always be regarded as a reaction of satiety. While a few infants may take solids as early as the age of 12 weeks, most infants because of motor immaturity are unfitted for solid food before the age of 16 to 20 weeks.
The authors do not worry much about sucking of the thumb, believing that it is spontaneous and indulged in by most children. "Attempts to