Lionel Sharples Penrose was born in London on 11 June 1898. He came of Quaker stock and was brought up according to the principles of the Society of Friends. The Quaker education he received and his service in the Friends’ Ambulance Train in France during World War I, immediately after leaving school, confirmed him in his compassionate interest in human suffering and in his detestation of war.

Even though I do not propose to discuss the work of Professor Penrose directly, I should like to express my appreciation to the organizers of this symposium in his memory for giving me an opportunity to pay tribute to a man whom I regard as having been both my teacher and my friend.

After I had agreed to give this talk about Lionel Penrose's contributions to genetics and mental deficiency I realized what an impossible task I had undertaken. His research career in these areas spanned a period of more than forty years, during the whole of which he was making important and significant contributions on an extraordinarily diverse range of topics. Furthermore, during this period both of these subjects advanced from an almost pre-scientific infantile state to rigorous and critical disciplines, and Penrose's work played no small part in this development.

Professor Penrose turned his attention to the subject of mongolism at a very early stage in his professional career and retained an undiminished interest in all facets of the problem for more than 40 years. His first publication in this sphere was in 1931 (1) and was entitled ‘The creases on the minimal digit in mongolism’. The observations he made in this publication are typical of some of his later ones. It reflected a mind alert to useful detail, in this case the fact that in some mongols there is only one flexion crease on the fifth digit instead of two. This peculiarity rarely occurs in the normal population and therefore provides an additional diagnostic criterion for mongolism. Particularly at a time when chromosomal examination could not be undertaken, this direct simple observation helped in the clinical delineation of a condition which is not always easily recognized.

Like other mental disorders, mental deficiency presents great problems in diagnosis. These diagnostic problems derive ultimately from the fact that a medical diagnosis can be made only in exceptional cases. Mental retardation is not a disease in itself, but only a symptom which may be found in a number of different conditions. It is true that there are a great number of oligophrenia syndromes with known aetiology, but together they represent a numerically small group. When one considers, in addition, that no clear cut distinction between the normally intelligent and the mentally retarded can be made, since the difference is merely quantitative, the difficulties of diagnosis become manifest.

The analysis of family data in the hope of detecting a recognizable pattern in the distribution of disease may be of value in respect of cause and of prevention. The recognition of classical Mendelian ratios, for instance, is both a partial explanation and an opportunity for genetic counselling which may lead relatives to take eugenic measures. In mentally subnormal populations, however, the occurrence of disease in families often shows more complicated distributions. From knowledge of the relationship between cause and distribution models may be constructed with which empirical data may be compared, for instance, in maternal-foetal incompatibility in respect of some antigen, or in polygenically determined diseases showing threshold effects in liability to disease.

Lionel Penrose's work was essentially concerned with medical genetics and, as this audience is well aware, especially with mental defect. He very seldom published in an anthropological journal, and on the few occasions when he mentioned anthropologists in his writings his remarks were not very complimentary. However, those of us who are in the business can take comfort from the fact that these remarks were generally aimed at an earlier generation of anthropologists who had failed to benefit from what human genetics already had to offer in the years before World War II.

Professor Penrose was a human geneticist but above all a human biologist interested in all aspects of man's adaptation and behaviours. However, I need not remind you of the fact that his interests were wider. They were, among others, with the field of biology itself. This interest was one reason why he was particularly delighted with some of the discoveries made on human chromosomes and their anomalies, and he shared very abundantly in the work and in the excitement of these discoveries.

In spite of increasing interest, the problem of the battered child remains controversial. Some see the problem as a response to stressful social circumstances and society's permissive attitude to violence (23), others view it as primarily a manifestation of parental maladjustment (64).

For some years EEG recordings have been carried out at the Maudsley Hospital on male persons charged with murder and in custody while awaiting trial. These recordings have been undertaken at the request of the prison authorities with the consent of the defence and irrespective of whether or not there was a recognized clinical indication for such a procedure. During the period 1964 to 1969 150 such prisoners were examined, only 97 of whom were subsequently brought to trial on a charge of murder, with the outcome as given in Table I. Towards the end of this period EEGs were recorded from 20 volunteer male members of the hospital staff, all within the same age range as the prisoners (mean age 30 years, range 16–70) and none with any previous history of obvious medical or forensic relevance.

Many surveys have been made of the course of schizophrenia, with results which may vary with diagnostic criteria, source and possible selection of patients, hospital admission and discharge policy (and facilities), and many other factors. The time scale is of particular relevance in view of the sometimes life-long course of the condition. Short-term studies thus have limitations to their value, and long-term surveys present problems, such as changes in fashions of diagnosis and management, which may affect their relevance at the time of publication. At present, there is much discussion of the relative roles of general hospital psychiatric units, mental hospitals and community care in the management of schizophrenia, and these organizational aspects are closely bound up and indeed are sometimes confused with the clinical course of the illness.

Multiple tics appear in the population with a frequency estimated at from 1 in 1,000 child psychiatric out-patients (Lucas et al., 1967) to 1 in 12,500 out-patients (Ascher, 1948). The incidence of XYY karyotype is about 1.24 per thousand males (Nielsen and Christensen, 1974). The occurrence of multiple tics with vocalization in a patient with the XYY chromosome constitution strongly suggests that the extra chromosome promotes neurological abnormality.

Considering their potential contribution to the community, the growth of clinical services in relation to the specialized mental health problems of students in higher education has been haphazard. Although most universities have developed or are on the way to developing comprehensive health services on the lines recommended in the report of the Royal College of Physicians (1966), services in the non-university sector are often less than adequate. This report accepted as established that about 5 per cent of students have psychological disorders which cause serious distress, and a further 10 to 20 per cent have less severe though handicapping disorders. It was accepted that special provision would need to be made for these mental health problems, as part of the range of preventive and treatment activities relevant to a College community.