The sensory material which provides the essential data for conscious activity is conveyed to the higher functional levels of the brain by impulses which stream up the olfactory tracts, the optic tracts, and the tracts of the brain-stem and spinal cord. With the exception only of the olfactory impulses, all these sensory impulses are filtered through the thalamic region of the brain, or diencephalon, before they can be relayed to the cerebral cortex which forms the anatomical substratum of the more elaborate mental processes. It is an interesting fact that, while the functional localization in the cerebral cortex and the functional localization in regard to the numerous fibre tracts in the brain-stem and spinal cord have been established in quite considerable detail by anatomical, physiological and clinical studies extending over many years, the localization and the connections of the various relay mechanisms in the diencephalon still remain obscure. Since the nature of the sensory material which is delivered to the cerebral cortex depends ultimately on the influences and modifications which may be imposed on the afferent impulses during their passage through the diencephalon, it becomes a matter of extreme importance, from the point of view of the study of the physiology of sensation and of psychological interpretation of sensory experience, that attention should be concentrated on this diencephalic mechanism. The minute anatomy of the diencephalon has recently been worked out in great detail, and it is now the task of the anatomist, physiologist and clinician to discover the functional significance of the numerous cell groups and fibre tracts which have been defined.

Present-day medicine tends, where the ætiology of a disease is obscure, to rely too much on the wholesale suspicion of several viscera. It is, therefore, necessary to consider those factors which lead us to the supposition that the liver is at fault in epilepsy.

In view of the increasing use of intravenous sodium evipan as an anaesthetic, any contribution to the knowledge of its pharmacology would seem to be of value. It is known from experimental work and from clinical reports that injection of this drug causes a depression of both respiration and blood-pressure, and that jactitations or twitchings are often present during induction. The report of the Anaesthetics Committee of the Medical Research Council (1) states that there is generally a decrease in the rate of respiration, and that there is a transient fall in systolic blood-pressure of 20–30 mm. Hg. Weese (2) observed a decrease in rate and amplitude of respiration, and a fall of blood-pressure of not more than 20 mm. Hg. Jarman (3) found a fall of 20 mm. or more.

A one-sided approach to any question, which is always suspect, becomes a very real danger when it concerns medicine. It is the purpose of this paper to draw attention to certain half-truths which have arisen in this way in connection with fear. Fear, like pain, is a danger-signal, called into existence to draw to the individual's notice the presence of some threat to his welfare. It has, therefore, ultimately a protective purpose with a direct relation to self-preservation.

This series of investigations originated in a study of the Necker cube. It has been suggested that the fluctuation-rate of this and similar ambiguous bodies will serve to differentiate between the introvert and the extravert. While this assertion was being investigated, it was found that those patients who were depressed showed a slow fluctuation-rate. It was decided to investigate the question whether or not the fluctuation varied with the degree of depression. Since the fluctuation-rate is known to vary considerably from person to person, it was decided to study a group of depressives over a long period of time, if possible until recovery. The stability of the fluctuation-rate in the same person from day to day is considerable. Guilford and Braby report a coefficient of reliability of ·96.