clinical material knows that, owing to the nature of things, even if it were possible to formulate a definition and thereby draw a line sharply distinguishing, for practical purposes, sanity from insanity, the line could be thus drawn only in relation to some more or less arbitrary standard of normality.

The need of standards of normality is felt not only in connection with attempts of enumeration of the insane in communities, but also in daily practice in connection with every case of alleged insanity in which commitment to an institution is sought; and in this respect the practice of the various states, varying as it does within wide limits, indicates the application of a whole series of fairly distinct, though not readily definable, standards.

Thus, referring again to the instances presented by Oklahoma and Massachusetts, significance attaches mainly to the consideration that there are undoubtedly many persons residing in the former state who are at large and whom, moreover, their fellow citizens do not consider proper subjects for an insane hospital, who would be promptly committed if they took up their residence in the latter state. In the last analysis, it is a difference in tacitly accepted standards of normality that accounts largely for the fact that in Oklahoma, as already stated, there were but 67 patients in institutions per hundred thousand of the general population, while in Massachusetts there were no less than 344.6; and similar differences in standards no doubt account for the analogous contrasts presented by statistics of the insane in institutions in the entire country at different times.

Persons are placed in institutions when, by reason of some mental defect or disturbance, their adaptation to their environment fails. The environment of a highly organized community with high standards of living is, of course, more exacting than that of a community characterized by a more primitive organization and lower standards.

Whatever may be one's theoretical conception of insanity, the line of division between it and the normal condition, as it is indicated by the practice of communities, is a shifting one, moving from the abnormal toward the normal extreme with the progress of civilization and the concomitant elevation of social standards.

These considerations are of importance, as they point a way to an indirect method of investigating the question which is before us, Is insanity on the increase? For, although it would be, of course, impossible to apply a newly-selected standard to conditions in the remote past concerning which we have no information other than that recorded by contemporary observers, it is at least within the bounds of possibility to apply such a standard in studying conditions in various parts of the country as they exist in our own time.

The states east of the Mississippi River may be divided into a Northern group, comprising Connecticut, Illinois, Indiana, Maine, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, and Wisconsin; and a Southern group, comprising Alabama, Delaware, Florida, Georgia, Kentucky, Mary

land, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia.

Facilities for the care of the insane have at all times been relatively more ample in the Northern group of states, and, accordingly, the number of patients in institutions in relation to the general population has always been greater, as shown in the accompanying table.

NUMBER OF INSANE IN INSTITUTIONS PER HUNDRED THOUSAND OF THE GENERAL POPULATION IN CERTAIN YEARS IN TWO GROUPS OF STATES EAST OF THE MISSISSIPPI RIVER.

The difference between these two groups of states is certainly very striking. From what has been said it would follow that the question, To what extent does this difference correspond with a real difference in incidence of insanity? is lacking in definiteness. It may be better expressed as follows: If the populations of the two groups of states, or representative portions of them, were exposed to the same environmental conditions, would there still be a difference between them as to the proportion of patients contributed to insane hospitals; and, if so, which group would contribute the higher proportion and how great would be the difference?

One advantage in thus expressing the question is that it affords a suggestion of a method for seeking

an answer.

A number of circumstances, such as availability of good statistics, the prevalence of high social standards, the composition of the population which is in certain respects peculiar, etc., combine to make the experience of the state of California worthy of special study in this connection.

The growth of the population of that state has for a number of decades been in large part by immigration from other states, especially those east of the Mississippi River. This fact has created an opportunity of making a comparison such as we desire to make, in order to find an answer to the question that is before us, by noting the number of admissions to the state hospitals of California contributed by natives of the above-mentioned two groups of states who have taken up their residence in California.

If the incidence of insanity differs materially in these two groups of states, it would seem that the difference should be revealed by this comparison one that is made on the basis of a standard which, though not to be theoretically formulated, is nevertheless fairly definite, uniform and readily applicable, namely, the standard of the prevailing environmental conditions of California.

During the biennial period ending June 30, 1910,1 the natives of the Northern group of states residing in California furnished 147.3 admissions to the state hospitals of California per hundred thousand of their general population. During the same period the natives of the Southern group of states furnished

1 Seventh Biennial Report of the State Commission in Lunacy of California.

166.7 admissions per hundred thousand: a difference of 13.1%.

In other words, as far as may be judged from these statistics, the Southern states east of the Mississippi River, which have had for many years, and still have, poorer and less adequate facilities for the care of their insane than the Northern, now show a higher incidence of insanity in their population.

Thus it would seem that the much greater relative number of insane in institutions in the Northern group of states is but an indication of a more thoroughly carried out policy of segregation, and appears to have already produced a demonstrable eugenic effect: for the application of a common standard to representative portions of the two population groups reveals evidence showing that the incidence of insanity is actually greater in the Southern group.

Similarly, it would appear that the progressive increase in the relative number of institution inmates, observed throughout the country during the past several decades, is also but an indication of more thorough segregation which has, in all probability, been attended by the same eugenic effect.

The conclusion seems justifiable, then, that such evidence as is available, far from showing that insanity is on the increase, tends to show rather that it is on the decline.

Prevention.1 As stated in the chapter on etiology, amongst the many causes of mental disease may be distinguished some few that are essential

1 A. J. Rosanoff. Causes and Prevention of Insanity. The Long Island Med. Journ., Sept., 1915.