One of the most obvious impediments to the advance of our knowledge of mental diseases is the lack of a physical basis of classification. This deficiency is constantly presenting itself, and even in such a comparatively simple disease as mania one is often in doubt as to whether the diagnosis should be manic-depressive insanity or confusional mania.

In previous papers it has been contended by Dr. Douglas McRae, Dr. Dods Brown and myself, that in cases of general paralysis there are special bacterial infective foci in the nasopharyngeal and buccal mucous membranes, and that these infective foci are of importance in the pathogenesis of the disease; Dr. McRae and I have also maintained that in cases of tabes dorsalis there are similar infective foci in the genito-urinary tract. In this paper I wish to deal with some further investigations, the results of which give additional support to these views. In the fifteen minutes at my disposal it is impossible for me to describe these investigations in detail. I can only indicate their chief results and state some of the conclusions that they seem to me to warrant. All the evidence that I can lay before the meeting is shown under the ten microscopes on the tables.

The very interesting publications by Dr. Ford Robertson and his pupils on the discovery of a bacillus as the cause of general paralysis of the insane have given rise to the following research.

The brief summary of the results stated in this paper is based upon an examination of thirty-five cases of general paralysis and seventy-seven cases of psychoses other than general paralysis.

It is not surprising that weakmindedness should be common amongst the habitual frequenters of prison, but the proportion of those who become certifiably insane is small. How very few are there of our ordinary asylum patients who come from the slums, or at least the criminal class. Is it that, in these less cultured individuals, crime and alcoholic excess take the place of insanity, each of them being a signpost marking distinct paths of degeneration, or does insanity exist, but is not recognisable as such? The unavoidable importance placed upon conduct in determining insanity amid the ordinary respectable conditions of life may prove misleading in the case of those in whom what is commonly called bad conduct is a normal condition. A distinguished alienist tells how he was once called to see a lady, and on being introduced to her she spat in his face. Without more ado he sat down and certified her. It may be that many amongst the criminal classes suffer from there being no possible obverse to this picture. I have seen men sent into an asylum suffering from delusions of long standing whose condition never caused their friends a serious thought till some Monday morning they refused to go to work, and before next pay-day they were certified. I have seen men sent to prison for habitual failure to support their wives or for neglect of their children where there seemed to be distinct mental enfeeblement, not certifiably obtrusive like a delusion, but in the particular circumstances as potent a factor in the lapse of conduct.

The object of this paper is to consider whether it is necessary or advisable to introduce ordinances for the discouragement of parenthood on the part of the “unfit,” and the encouragement of large families on the part of the “fit,” in fact the eugenic principle, and to those who believe that the only true cure of insanity is its prevention, the subject must be of vast importance.

It is only within the last few years that any serious attempt has been made to investigate the viscosity of the blood and to find out what importance, if any, could be attached to the variations in the fluid friction of the blood in health and disease. Prior to this period a few physiologists did pay attention to this subject, but many of their results have been ignored on account of the difficulty encountered by the coagulation of the blood. Defibrinated blood or blood to which an anti-coagulator had been added was used in later investigations.

Manifestations of anæsthesia, mental confusion, and moods are frequently met with in general medicine and psychiatry. Their occurrence is not confined to pathological states; in normal people it must be studied in the domains of physiology and psychology. It is by no means always easy to differentiate the physiological from the pathological, or in psychology the normal from the abnormal. This difficulty in demarcation has tended to render investigation arduous and the findings imperfect.

I have been asked by the President to open a discussion on the “Treatment of Mental Excitement in Asylums.” The subject is a very important and practical one, and goes to the root of many of the most difficult problems connected with the management of the insane. Of cases of mental excitement in asylums it may be said, “they are always with us,” and the manner in which they are treated and the success attending their treatment may be taken as tests of the good management of an asylum. The difference between the state of the madhouses of the past and of the mental hospitals of the present day is largely the result of better methods of dealing with it.