In the two previous lectures of this course the subject of “Variation in its Relation to the Origin of Physical Malformations, of Congenital Mental Defect, and of the Neuroses, such as Epilepsy, Hysteria, and Alcoholism,” was considered. The correlation between congenital malformation and congenital mental defect was pointed out. The relation of the neuroses to one another, their heredity, and their distribution throughout mankind of all races, was insisted on. It was also shown that all these affections are genetic in origin and independent of so-called causes or influences due to the environment. For the environment is not, and cannot be, constant while the manifestations in question are, so far as we know, universal. It was further shown that congenital malformation and congenital mental defect are due to inherent processes, the nature of which is at present unknown, acting within the fertilised ovum. It is, moreover, certain that these processes must be independent of the environment of the elements contributed by either parent, of the immediate state of health of the parents or, with certain exceptions such as injuries or special disease, of the uterine environment. It is not asserted that diseases affecting the mother or even, on rare occasions, specific affections of the father may not deleteriously influence the growing embryo in utero. The fact remains, however, that in the majority of instances these defects are hereditary, that they may pass over several members of the same family, and in the case of animals over several members of the same litter—nay, even that they pass over one or more generations to re-appear in a succeeding one. In face of such facts, it is useless to speculate upon physical causes while the great innate cause remains obscure.

Workers in the finer structure of the nervous system are suffering from a plethora of observations. New and more searching methods are being discovered every day, and no sooner does he who sets about constructing a scheme of the central nervous system arrive at something which appears to be satisfactory than he has to pull it to pieces and reconstruct it, to fit in further detail which has been brought to light in the meanwhile. Until this vast array of observations has been properly digested, a process which may well take years, we can scarcely hope to obtain a scheme of the relationship of the nerve-cells to one another which will be more than a working hypothesis.

The following paper consists of further instalments of a research which has been conducted by the author for several years and which deals with the general pathology of mental disease from both clinical and pathological standpoints. The essential bases of a scientific general classification of mental diseases are a morbid anatomy and a general pathology. Before the latter problem could be successfully attacked a prolonged study of the structure and mode of development of the cell-layers of the cortex was necessary. This was commenced by a lengthy investigation of the region of the cortex concerned with the special sense of vision, and a paper on this subject was published in 1900.(1) This paper dealt, by the method of micrometric examination, with the general histology of the regions of the cortex cerebri concerned in the immediate reception (projection centre) and the elaboration (lower associational centre) of visual impressions; and the research resulted in the exact localisation of the primary visual area of the cerebral cortex. This region was described by the author as the “visuo-sensory” area, and to the surrounding area of visual association he applied the term “visuo-psychic.(2) The results obtained from this study of the cortical areas concerned with one special sense were considered sufficient for the purposes of the research, and the region of the cortex cerebri which occupies a higher plane in the hierarchy of cerebral function than those concerned with sensory reception and elaboration was then taken into consideration. Before, however, it was possible to apply the same method to the region of the cortex cerebri concerned in higher association and the general orderly co-ordination of psychic processes, it was first necessary to satisfactorily determine the particular part of the cortex which possesses these functions, as this is the subject of grave dispute on the part of different authors.(3)

Kahlbaum in 1863 described a form of mental disease occurring at puberty and rapidly terminating in dementia; this he called “hebephrenia.” In 1874 the same author described the condition known as “katatonia” or the “insanity of rigidity.” These terms do not appear to have been adopted till 1891, when Pick, under the heading of “dementia præcox,” described cases, including hebephrenia, characterised by maniacal symptoms followed by melancholia and rapid deterioration. This term has now been extended by Kraepelin to include the “hebephrenia” and “katatonia” of Kahlbaum, together with certain forms of paranoia which undergo early deterioration.

The following paper is an attempt to deal with statistics in insanity according to a scheme which observes the fundamental canon of statistical accuracy, which interprets the true spirit of lunacy legislation, and which serves the essential purpose of medical utility. I may divide the paper into three parts:

While the Association is engaged in considering the proposals of the Statistical Committee, it may be helpful to note what has been written about insanity from the point of view of a librarian. The following extended classification has been found adequate for the arrangement of some 1,500 books and pamphlets relating to this subject. An authors catalogue is easily prepared upon the usual dictionary plan, but it assumes a wide knowledge of literature, not only as a matter of history, but also as an incessant and overmastering growth. A subjects catalogue, on the other hand, is the method of importance to workers who, with the least possible delay, want to ascertain what has been written on all or any of the various aspects of the main subject engaging attention.