This resulted in very hard straining on her part, with all the signs of physical effort (explosive breathing sounds resulting from the setting of the larynx, rush of blood to the head, seen in the flushing of the face, etc.).

The number of experiments in each series was intentionally made very small, from one to twelve, in order to avoid fatigue.
The results were now very interesting.

During the month ending June 15th the child showed no decided preference for either hand in reaching straight before her within the easy reaching distance of ten inches, but a slight balance in favour of the left hand; yet she was right-handed to a marked degree during the same period as regards movements which required effort or strain, such as grasping for objects twelve to fifteen inches distant.

For the greater distances, the left hand was used in only five cases as against seventy-four cases of the use of the right hand; and further, all these five cases were twelve-inch distances, the left hand being used absolutely not at all in the forty-five cases at longer distances.
In order to test this further, I varied the point of exposure of the stimulus to the right or left, aiming thus to attract the hand on one side or the other, and so to determine whether the growth of such a preference was limited to experiences of convenience in reaching to adjacent local objects, etc.
The deviation to the left in front of the body only called out the right hand to greater exertion, while the left hand fell into still greater disuse.

This seems to show that "dextrality" is not derived from the experience of the individual in using either hand predominantly for reaching, grasping, holding, etc., within the easiest range of that hand.