Jung wrote his Type Psychology in 1914, but does not seem to have developed any further its general thesis. The terms “introvert” and “extravert”, however, have slipped into everyday language, and experimental studies and questionnaire inquiries on introversion-extraversion continue to be published in psychological journals. Ink-blots, ambiguous figures, and even knee-jerks are called upon to measure this fundamental tendency of man; inventories and self-rating sheets are employed widely to estimate it; and yet it appears to evade capture. There is as yet little or no evidence anywhere that a coherent tendency of the kind looked for does in fact exist.

The investigations reported in this paper owe their origin to a systematic research on the fibrous glia in various groups of mental defectives. A preliminary note on this subject has already been published by A. Meyer and L. C. Cook (1937). For technical reasons the full report on these findings will be delayed. A special publication on the findings in mongols seemed to be desirable, not so much because they are thought to constitute the substrate of the mental defect in mongolism, but because they are so unusual that they deserve special mention. In addition, they throw some light on the findings and interpretations of previous workers.

It has been recognized for many years that in certain cases of mental disorder there is a demonstrable disturbance of carbohydrate metabolism. Among early observations may be mentioned those of Raimann (1902), Schultz and Knauer (1909) and Laudenheimer (1898). These workers reported the presence of sugar in the urine of patients suffering from depressive and anxiety states, and noted that the glycosuria often varied with the severity of the mental disturbances and disappeared with them. They remarked, however, that the phenomenon was of little diagnostic importance, inasmuch as it could be found in depressive states associated with many different types of mental illness. Such observations were of value as an indication for further research, but until it was established that the glycosuria was not due to a derangement of the renal mechanism of sugar excretion, it could not be claimed that the findings indicated such a fundamental metabolic disturbance as is now known to exist. Although Santenoise and Tinel (1923) stated that the renal threshold varies according to the mental state of the patient, many more recent workers have shown that the increased sugar excretion is always associated with a greater or less degree of hyperglycæmia, and, although agreement on this point is not complete, the balance of evidence favours the belief that such hyperglycæmia is alimentary in origin, and not spontaneous. As the earliest workers appeared to recognize, the metabolic disturbance is found mainly in states of depression, which may be retarded or agitated, and in certain cases of schizophrenia, which, too, may be stuporose or restless. Some investigators are of the opinion that the same disturbance may be found in states of mania as well as or even to the exclusion of depressive states, but this is a view which is held only by a minority.

The problem of devising scientific means of assessing and describing the personal characteristics of an individual has been attacked along a number of lines, of which the principal, perhaps, has been the attempt to separate independent variables by the use of tests, which, it was expected, might be the subject of progressive refinement through study of the intercorrelations of scores obtained with them. So, starting with the admittedly imprecise categories of common discourse, and the adjectives commonly used in the description of individuals, it was hoped that by degrees it would be possible to disentangle the basic variables to which personality and character are subject, and to provide the means of assessing each by the use of a particular test. It can scarcely be said that these hopes have been realized. The categories in question have eluded the refining power of test score factorization.(1)

To the student of mental deficiency the lower grades of oligophrenia offer endless opportunities for the exercise of his diagnostic acumen, and in this largely unexplored terrain there are doubtless many syndromes awaiting discovery.

The literature on the drawings of schizophrenics is mainly concerned with their spontaneous artistic production. Some schools of psychotherapy use drawings systematically as an approach to the patient, i.e., as another way of obtaining free association from them. But apart from this, little work has been done on experimental drawing for diagnostic purposes. There is, however, the interesting work carried out by Mohr (1), who analysed drawings of mental patients of various kinds, and demonstrated in their production numerous clinical symptoms. His paper, classical as it is, has not stimulated many others to follow his lines. Sapas (2) collected systematically drawings of mental hospital inmates, which, in fact, were tests of visual memory. She followed, in her investigations, the technique originally proposed by Hickson in his work on The Mental Fingerprint. Lately, Becker (3) has contributed to the problems involved, in a systematic study, which will be referred to later.

A brief note upon the physical characteristics of three cases of phenylpyruvic oligophrenia may be of interest for comparison with other cases. The three patients have been under special observation for 2½ years, and are the only definite cases discovered in an examination of 2,300 mental defectives of both sexes, all ages and all grades.

In the extensive literature on sleep therapy some fifty complications have been recorded by the various authors. In a previous article (Journ. Ment. Sci., November, 1937) these were listed (pp. 660, 661) and divided into four main groups as follows:

1. 1. Common complications: Representing mainly normal by-products of the treatment.

2. 2. Complications involving particular tissues: Representing tissue idiosyncrasy.

3. 3. Accidents.

4. 4. True toxic complications: Representing a group which could not be regarded as either a necessary by-product of the treatment, an unavoidable expression of disproportionate sensitivity on the part of a particular tissue, or an accident which might be avoided.