As has been already suggested, one of the most important characteristics of all these tendencies is their modifiability.  The very ease with which they can be modified suggests that this is what has most often to be done with them.  On examination of the lists of original tendencies there are none which can be kept and fixed in the form in which they first appear.  Even the best of them are crude and impossible from the standpoint of civilized society.  Take as an illustration mother-love; what are the original tendencies and behavior?  “All women possess originally, from early childhood to death, some interest in human babies, and a responsiveness to the instinctive looks, calls, gestures, and cries of infancy and childhood, being satisfied by childish gurglings, smiles, and affectionate gestures, and moved to instinctive comforting acts of childish signs of pain, grief, and misery.”  But the mother has to learn not to cuddle the baby and talk to it all the time it is awake and not to run to it and take it up at every cry, to steel her heart against the wheedling of the coaxing gurgles and even to allow the baby to hurt himself, all for his own good.  This comes about only as original nature is modified in line with knowledge and ideals.  The same need is evidenced by such a valuable tendency as curiosity.  So far as original nature goes, the tendency to attend to novel objects, to human behavior, to explore with the eyes and manipulate with the hands, to enjoy having sensations of all kinds merely for their own sakes, make up what is known as the instinct of curiosity.  But what a tremendous amount of modification is necessary before these crude responses result in the valuable scientific curiosity.  Not blind following where instinct leads, but modification, must be the watchword.

On the other hand, there are equally few tendencies that could be spared, could be absolutely voted out without loss to the individual or the race.  Bullying as an original tendency seems to add nothing to the possibilities of development, but every other inborn tendency has its value.  Jealousy, anger, fighting, rivalry, possessiveness, fear, each has its quota to contribute to valuable manhood and womanhood.  Again, not suppression but a wise control must be the attitude of the educator.  Inhibition of certain phases or elements of some of the tendencies is necessary for the most valuable development of the individual, but the entire loss of any save one or two would be disastrous to some form of adult usefulness or enjoyment.  The method by which valuable elements or phases of an original tendency are fixed and strengthened is the general method of habit formation and will be taken up under that head in Chapter IV.  When the modification involves definite inhibition, there are three possible methods,—­punishment, disuse, and substitution.  As an example of the use of the three methods take the case of a child who develops a fear of the dark.  In using the first