The intention of the present paper is to give an impressionistic account of the cases seen rather than a detailed and analytical description which is necessarily beyond its scope.

The subject of the relation of recurring dreams of adult life to that almost inseparable mixture of real experience and fantasy which forms the mental life of the child was dealt with by Rudyard Kipling in The Brushswood Boy, and by George du Maurier in Peter Ibbetson, after a fashion not given to psycho-pathologists. The psycho-analytic school has of late years endeavoured to trace the genesis of the psycho neuroses to aspects of the same period generally considered less attractive. There has, I think, been less effort to establish such a connection in the major psychoses.

Change of phase is a well-recognised feature in the course of certain of the psychoses. In manic-depressive insanity it is on the phasic variation of the affective state that the separation of that type of mental disorder is based. So, also, in many cases of the chronic psychoses phase changes occur as the disorder progresses, and as the patient fits in new experience and builds up fresh mental content on the basis of the already existing delusional state.

Among the many important advances which have taken place within recent years in the science of medicine, none have surpassed in value or in extent those affecting the nervous system. One of the principal points which these have established, no matter from what direction the subject has been approached, is the recognition of the essential unity of the sciences of neurology and psychiatry. In the domain of psychological medicine, the researches of Freud and Jung on psychopathology and their theories of the subconscious and its manifestations have provided a common meeting-ground; the investigations of Campbell on the cell lamination of the cerebral cortex, and later of Shaw Bolton, have aimed at the elaboration of a scheme of cerebral function based on clinico-histo-pathological proof; the studies of Elliot Smith on the comparative anatomy of the brain and the development of the cerebral cortex peculiar to the mammalia have demonstrated some of the factors which have contributed to the attainment of man's distinctive mental aptitudes, and eventually made possible the emergence of the human intellectual abilities culminating in the development of speech, and the attainment of intellectual pre-eminence within the human family; equally important is the recognition of the integrative action of the nervous system by Sherrington, and his views on the importance of the simple muscle-nerve preparation in explaining the processes involved in cerebral association and the significance of excitation, inhibition and the latent period; and still more recently we have the investigations and publications of Schafer on the influence of the endocrine glands on the nervous system, and of Mott on the relationship of the reproductive and endocrine glands to mental disease, and the light which this has shown on the ætiology of dementia præcox.

The subject of biochemistry is so closely related to physiology that any advances in the former science are bound to have important applications to the practice of medicine.

General paralysis is often very difficult to diagnose, and the responsibility of coming to a decision is not lessened by the fatal character of the disease. Amongst the protean manifestations of neuro-syphilis, the early and definite recognition of this, its most deadly and intractable form, offers a problem in nice discrimination—a problem which is in the present tense and imperative mood. According to Southard, of 119 cases diagnosed as general paralysis, post-mortem examination revealed a diagnostic error of 26 per cent. If anyone had been able to devise a less intricate test for syphilis, the Wassermann reaction would never have survived to the present day. It is one of the most complicated methods that have been applied to diagnosis in medicine. Any simple test, therefore, which promises increased precision in diagnosis, is worthy of that careful investigation which is the half-way house to knowledge.

In this paper I should like to emphasise the technique of the colloidal gold reaction rather than the results I have obtained, for the cerebro-spinal fluids I have been so far able to examine have been mostly from cases of dementia paralytica, and, though the results are interesting and suggestive, the number of cases is too limited to allow one to dogmatise on the findings.