Primitive brains and intelligences, whether in earliest man, utter savages, young children or the feeble-minded, find it difficult or impossible to handle abstractions fast and rationally; on the other hand, interest and skill in cerebrizing the abstract, pro tanto is an index of high intelligence. On this “perfectly good” psychological basis psychiatrists as a class are persons intelligent above the average, and properly may be so considered. Thus it may be assumed that if they do not continuously bring into use every available aid and contribution to their science (and probably most of them do not), it must be mostly due to lack of opportunity and of habituated interest. And that, of course, is the still obvious fact.

The nervous system of all vertebrates is built up of long conducting, specialized cells, termed neurons. In order to function, these neurons, or nerve-cells, must be linked together in chains or arcs. Each neuron in the chain or arc is structurally separated from other neurons by a break termed a synapse. The structural elements of a neuronic arc are, therefore, as follows:

1. 1. A sensitive receiving organ—the receptor or sense-organ.

2. 2. A centrally conducting receptor bipolar neuron.

3. 3. One or more short connector or internuncial neurons.

4. 4. A peripherally conducting effector multipolar neuron.

5. 5. An effector apparatus—for example, a muscle or a gland.

When a patient is admitted to a mental hospital his condition is investigated from a number of angles. His physical state is ascertained, including the condition of his blood and his cerebro spinal fluid; he may be found to exhibit such and such a neuro logical symptom. His mental state is probed into, his intelligence estimated, his emotional reactions noted, his complexes even may be progressively dug up. As a crowning summit to this edifice of knowledge a label is at last attached to the case, and a diagnosis arrived at.

I should not have ventured to read this paper before such a distinguished audience had I not been specially urged to do so by your President. If, therefore, at its conclusion you have any or, it may be, much criticism, you must at least divide it between him and myself. I accept full responsibility for an inadequate and imperfect presentation of my thesis, but for the attempt itself he must take all the blame.

Psychiatry in its literal sense is the medical treatment of mental disorders, which necessarily implies the scientific investigation of the nature and causes of these disorders. Psychiatry is therefore indissolubly linked with the medical and biological sciences, and participates not only in their solidarity, but also in their unrest, for every advance in these sciences intimately affects its outlook. In addition it has undergone—and is still undergoing—vicissitudes peculiar to itself which are unknown in other departments of medicine.

An invitation to address a gathering of medical psychologists is, to the physiologist, a great temptation, and on such occasions he is apt to leap into the whirlpools of psychology in an attempt to explain the workings of the brain by hypotheses based, alas, on insufficient evidence. The paucity of information on cerebral function in physiological text-books has an explanation. Our lack of knowledge is due to the absence of available methods for investigating the normal activity of the higher nerve centres. Explanations are too often advanced without a due appreciation of the function of the lower nervous system in bringing about the exquisite co-ordination and relationship that exists between the different areas and organs of the body. This function is well exemplified in the reciprocal innervation of which we have evidence with every normal voluntary contraction. The difficulties of investigation have their root in the complexity of the reactions of an animal endowed with a well-developed cerebral cortex, compared with those seen in the lower types of life, or in the spinal animal. It must be clear that if our knowledge of the physiological factors controlling mental activity is to advance, the physiologist must continue to make measurements, accurate, quantitative measurements, if possible, on structures which he can control, and on preparations in which he is able to isolate the disturbing factors, and from these results and conclusions to construct by slow degrees a knowledge and understanding of the nervous system.

In order to obtain a complete account of these facts and factors from every available source, and to get the co-operation on behalf of the patient, it is necessary that the relatives, the physician and the nurse of the patient be presented with the data in a comprehensive form.

The Royal Commission on Lunacy and Mental Disorder was set up in July, 1924, to inquire into a matter of urgent public importance, that is to say:

1. (1) The existing law and administrative machinery in England and Wales in connection with the certification, detention and care of persons who are, or who are alleged to be, of unsound mind.

2. (2) The extent to which provision is or should be made in England and Wales for the treatment without certification of persons suffering from mental disorder and to make recom mendations.

When the patient, F. E—, handed me the MSS. entitled “Hallucinations and Sanity,” I recalled a paper read to this Association some ten years ago by the late Dr. Hunter Steen—a paper which Sir George Savage at the time styled as “mosetncyclopædic” (vide Journ. Ment. Sci., 1917, pp. 328 and 437). In the course of a most instructive discussion following on it, some points were raised which are especially noteworthy.

In 1894 the term “perseveration” was first used in psychiatry by Neisser to indicate abnormally persistent repetition of an activity after the activity should have been completed, such as is shown in the frequent speaking or writing of a word or words in unsuitable places. Thus originally the term was descriptive of a particular and circumscribed symptom to be recognized in the clinic. In 1900 the term was used in psychology by Müller to indicate the tendency which every idea has, after having once occurred, to remount spontaneously into consciousness.

We are all familar with the clinical picture of a case of epidemic encephalitis of the Parkinsonian type: the fixed flexion attitude, festinating gait, mask-like face and general slowing of all voluntary movement. What is the explanatory pathology of each and all of these physical signs ?

There are many references in neurological literature to pathological changes in the globus pallidus in diseases accompanied by muscular tremor and rigidity, such as paralysis agitans and post encephalitic Parkinsonianism.

This sequel of encephalitis lethargica has attracted much attention on account of its great frequency. It was found in 70 out of 129 cases studied by Mme. Lévy. In the earlier pathological studies of the syndrome attention was focussed chiefly on the midbrain; recent researches have proved that the changes in the nervous system are more widespread than were at first apparent.

I do not propose to attempt any critical review of what has already been written on the subject which forms the title of this paper, but merely to lay before you my own experience. At the same time I may remind you that there is distinguished support for the view that a close association exists between insanity and disturbances of the cerebral circulation caused by cardiac defects.

The literature dealing with coliform intestinal bacteria in patients suffering from mental disorder is extremely scanty. Goodall, Journal of Mental Science, 1927, p. 368, writes: “As resgards our knowledge of the intestinal tract as a source of infection I consider that the position is still very unsatisfactory. … For a few years prior to 1914 my colleagues and I at the Cardiff Mental Hospital Laboratory had carried out much tedious work on the bacteriology of the faces in states of acute melancholia and mania.