been retarded may entirely make up for such retardation by a later period of rapid growth, but the conditions for the rapid development must not be supplied too late or the power to grow is likely to be lost. A period of rapid growth in height after eighteen and in intellectual ability after thirty is rare. Permanent retardation in physical development at an early age produces the dwarf and in mental development, the feeble-minded individual. Many feeble-minded are such simply because they retain the characteristics of childhood at a certain stage of development, instead of developing those of later stages.
The natural order of development in children is very difficult to determine because of countless individual peculiarities. Children of the same age sometimes differ as much in some particulars as one group of children differs from another several years older or younger. This makes it necessary in order to get reliable truths regarding changes with development, either to compare a large number of children of different ages or else to study the same child for many years. Both of these methods have been used and the results of detailed continuous study of individuals, confirm and supplement the results obtained from the study of a large number of children of different ages. In both forms of study care is needed to determine whether the changes that are found to have taken place are due to inner laws of development or are the result of special conditions affecting the development of the individual or the group. On the scientific side, it is important that the inner laws of development shall be determined, while on the practical side it is necessary, if the wisest course is to be pursued, to know what the natural tendencies of development are at each age and how children are modified by special surroundings and modes of treatment.
According to an old view of human nature all natural tendencies should be opposed, while according to another extreme view they should all be encouraged. The medium and common-sense view is that in this, as in other cases, we should know the nature of that with which we are dealing, in order that we may do what we wish with it, at least expense of time and effort.
It still remains to be determined, however, as to how quickly, and by what means, one should seek to bring about changes that are desired. Some, like the gardener, believe in making the conditions favorable for the development of the plant, while others try to force an early development and even pull open the buds before they are ready to blossom. There is a growing belief that nothing is gained by haste and that undesirable tendencies are usually best treated, not by direct opposition and attempts at uprooting, but by utilizing them in harmless ways for the development of opposing tendencies. One illustration will make clear this principle. Dr. C. F. Hodge, of Worcester, found a lot of toads that had been killed by school boys. Although indignant, he, after a
