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.

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 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.

Experience of neurotic patients seeking treatment convinces me that paranoia is by no means so rare a disease as asylum statistics would lead one to suppose. For the purposes of the latter, of course, only fully developed and alienated cases are taken into account. Of the four cases to be discussed here, only one has said or done anything that could be recorded in a certificate, and the delusional picture was only unfolded at the patient's goodwill. None of these cases therefore would figure in statistics, yet all four are drawn in a short space of time from a limited section of the community. Paranoid trends, episodes or systems are, I believe, quite common in intelligent, cultured and well-developed minds, and account for a substantial amount of insufficiency and unhappiness. Apart, therefore, from the question of the treatment of the delusional asylum patient, the projected mental clinics will find themselves faced with a formidable problem in regard to the treatment of paranoid conditions. It is from the incipient and partial cases of paranoia that we can gain an insight into the factors which arrest or promote the disease. Only in the most exceptional cases does the fully developed paranoiac admit us within the circle of his fortifications.

At the outset of this communication let it be said that the intention is not to make any new or original contribution to the subject, but to re-state some old facts which, it seems to me, are in danger of being forgotten by the older ones amongst us, and have not been sufficently impressed upon those who have recently come to the study of general paralysis. My own experience leads me to hold suspect the way the diagnosis of this disease is arrived at to-day in many quarters, and consequently to question the validity of many published statistics. In the time at my disposal it is not possible to alter settled beliefs, but I hope to arouse doubts and to shake some confident and easy convictions. If the doubts be carried into the study of future cases my object will have been attained.

The rationale of the malarial treatment of general paralysis has not, so far, been thoroughly understood. It has been believed by some that the remission is due to the destruction of spirochætes in the cortex by the intermittent waves of high temperature, which leave them no time to organize a defensive mechanism. This explanation assumes that the destruction of the spirochæte with, perhaps, its removal from the brain may result in a cessation of the active progress of the disease and, in some cases, in a complete return to normal cerebral function.

It is well known that injection of protein substance into the blood causes the appearance in the blood of antibodies to the protein. Injection of bacteria is followed by the appearance of several kinds of antibodies, and the substances which produce “clumping” constitute one, or rather two, of these antibodies. The appearance of agglutinins in the blood following vaccination or infection has been shown to occur regularly in such a large number of individuals, and in animals, that there can be no doubt that this production of antibodies is a natural phenomenon connected with successful resistance to the deleterious effects of the organisms. Non-production or abnormalities in the production of agglutinins following injection of bacteria represents a pathological process probably of the nature of sepsis.

Wakefield Mental Hospital was opened in the year 1818. Within a few days there appear in the case-books notes describing patients suffering from diarrhœa with blood and mucus. During the years 1818 to 1910 these or similar notes appear with such monotonous regularity that it would lead an outsider to believe that dysentery and its allied diseases were natural or at least unpreventable in asylums.

Fæces sent to the Laboratory for search for dysentery or typhoid organisms are plated direct on to three previously dried “Rebipel” agar plates by means of a stout platinum wire bent at right angles. The inoculated plates are incubated at 37.5° C. for 18–24 hours and are then examined for suspicious colonies.

In this investigation of blood-pressures in the various forms of insanity, 920 male cases were examined. In order to reduce the numerous variable factors to a minimum, the following procedure was adopted.

Further consideration of the theory that mongolism is caused by a fcetal hyperthyroidism ceasing at birth shows that much can be added to support this view.