might enter in and take possession if the original inhabitant was found absent, or might even dispossess the original owner. Hence the actions of a person might be attributed to possession by "evil spirits," and that chapter of human history dealing with demoniacal possession is both interesting and harrowing.

It has long been seen that actions of men were in some way dependent upon circumstances, upon education and upon health, hence such words as "afflicted" or "gifted" are rather vague. There has come, nevertheless, recognition that the human race grades from those of the lowest mental caliber to those of the highest. Using present terms we may roughly classify men into the following groups:

The Subnormal-The Feeble-minded: Idiot, Imbecile, Moron.

Normal-minded - The Common People.

Supernormal - The Distinguished, the Genius.

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Before we attempt to consider these separate classes we must again emphasize the difference between endowment and attainment. Though we cannot put our hands upon the actual physical traits, we know that men differ by nature as well as by nurture. In every-day life it may impossible to determine the actual contribution of these two factors. This backward child in the schoolroom may have a normal mind which has been poorly trained, or it may be weak through lack of food. It may be suffering from disease, or it may have been crippled by some accident. The distinguished man may be one of only ordinary capacity who has been unusually well trained, or has had the superior opportunities which wealth and social position bring, or who accidentally has done that which has brought renown; or he may be mentally far above the

average. Suspending our judgment on these questions for a time, it is not hard to see that in actual life the unsuccessful are likely to drift into public institutions and become public charges, while the successful rise into public esteem. Nevertheless, capacity is not necessarily shown by position. The generals who shine on the parade ground not infrequently have to be replaced in time of war by others whose talents have not been highly esteemed ere the army wins any notable victories.

Recalling our ignorance of the brain and the necessity of depending upon actions for evidence, it becomes plain why we had to wait for a system of compulsory general education, which involved sending the mass of the children through a given program and the attempt to do this at a given rate, before we could even devise any tests of mental growth and ability. The best that we have were worked out after very careful study of French children by Binet. They are designed to show us the mental age of the child. A boy of ten, let us say, can pass the tests ordinarily done by a child of eight. We say then that his mental age is eight. This tells us nothing of the cause of his retardation. In actual use these tests have proven very satisfactory up to the age of 12 or 13. Many have objected to them on the ground that adults could not pass the tests, but the objection is not well taken. By the same token few college professors could pass the freshman entrance examinations, yet their development is evidently greater than that of freshmen. That these tests in the hands of the inexperienced have often been used to prove feeble-mindedness is unfortunately true, but the trouble lies in the observers, not in the tests. It may be true that when a child is found over two years behind those

of his age he is feeble-minded, but this must be demonstrated.

For about a century we have been gathering into special institutions the feeble-minded. Regardless of actual age they are always children no matter whether they have grown up in the neglect of the back woods or in some almshouse or have been given the best of medical care and educational opportunities. They are different from normal children in their rate of growth, in their death rate, in the coördination of movements and in facial expression. In 2,801 cases in institutions in America the age at death was 20.3 for idiots, 22.9 for imbeciles and 28.5 for morons. They may have remarkable memory, but it is a memory of unconnected and unrelated things, as for instance sentences from a foreign tongue of which they have no understanding. They may have considerable musical ability as did the ex-slave Blind Tom, and yet be unable to master the third reader. They may have the strength of the adult and be able to do all sorts of simple tasks and yet be unfit to care for themselves.

In the earlier years only the lower grades were recognized. These in the lowest group are known as idiots who remain mentally under the age of two; that is, they do not learn to talk, though the ablest among them may use some words. This group is, of course, wholly dependent upon their keepers and often cannot care for themselves in the simplest of bodily functions. They vegetate rather than live.

Above the idiot is the imbecile, who ranges in mental age from three to seven with a corresponding development of powers. They seem physically weaker than normal children of the same age. As their mental powers rise

the coördination of body movements and facial expression approaches the normal. They can be trained to do all the tasks within the grasp of a child of corresponding age, and thus may do much in the way of caring for themselves, always under supervision.

Moron is the term recently applied to the highest group now classified with the feeble-minded. They range from the upper limit of the imbeciles to the mental age of perhaps 12. This highest group are so much like the normal that they have not always been distinguished and would often be unrecognized by the inexperienced. Even institution superintendents ten years ago denied that they differed from the normal. Dr. Barr, the head of the great school at Elwyn, Pennsylvania, claimed, however, that above the feeble-minded was a class which he called the moral imbecile. He thought that they were normal in all things except in their inability to distinguish right from wrong. Our newer tests have shown that we were merely dealing with a feeble-minded group of higher mental age.

In the earlier days of the study of the defectives it was thought that a sharp line separated them from the normal. Now it is seen that the one shades into the other by imperceptible degrees. Because the lower grades are so easily distinguished from the normal it was thought that their numbers were very limited. Now, as the higher grades are recognized and more accurate surveys are made, it is clear that the number is far larger than had been thought and there has been a growing recognition of the importance of the problem they present. It becomes then a matter of more than passing interest to discover the cause of this condition.

Ordinarily feeble-mindedness is not detected until the

age of infancy is past. Then the child fails to keep up with its fellows and the parents begin to inquire as to the reason. Finally, the mother recalls that at the age of six months the child had a severe fever, or fell from a chair and bumped its head and this fact is then held to be the cause of the trouble. This may be true, but we should not forget that the cause is recalled only after years have intervened and that probably something else also happened which might have been fixed on had not the particular incident been remembered. That is to say, the parents were looking for a cause and were certain to find one. The difficulty is that every child at some time bumps its head hard, or has some sickness, yet only a few fail to develop subsequently. At the other extreme stands the fact that we have no record of two feeble-minded parents producing a normal child. There are such parents with normal children in the family but we cannot always be sure of the percentage of the normal members. In the famous case cited by Goddard the normal children were mulattoes, while both the reputed parents were white. Moreover, where one of the parents is feeble-minded some, occasionally all, of the children are feeble-minded. In other cases, though the parents are both normal, investigation proves that some of their ancestors were feeble-minded. Such phenomena were extremely puzzling until the development of biology and the discovery of unit characters offered possible explanations. Some of the actual family histories may now be considered.

There is no better case than that which formed the beginning of the survey made by the Training School at Vineland, New Jersey, which Goddard details in his valuable book, "The Kallikak Family."