POROKERATOSIS.

866 within eight days from the date of the appearance of the initial case of the outbreak. In addition there were 11 secondary cases. Inquiry showed that of these 33 primary cases 28 had definitely eaten suspected food, certain " head-cheese," a form of brawn, and the other five had eaten beef bought and served at the time when the suspected brawn was purchased. Circumstantial information from certain individual cases shows clearly that the source of infection was the No substance called in the report " head-cheese." samples were available for bacteriological examination. but the food was prepared and sold by the proprietor of the meat market and his wife. It was ascertained that the wife had been ill, for a period of approximately four days, about three weeks before the outbreak. She assisted in preparing the suspected food two days before it was placed on sale. It was not found possible to examine her blood serologically, so the presumptive evidence that she was the cause of the outbreak could not be tested. The little outbreak is of interest from two points of view. One is that recorded outbreaks of paratyphoid fever from contaminated food are still comparatively rare. The chief point of interest is the light it throws upon food-poisoning outbreaks. The prevailing German view, one also largely followed in America, is that the food-poisoning bacilli of the B. aertrycke or B. suipestifer types are identical with B. paratyphosus B-i.e., in other words, that the same bacillus may at one time cause paratyphoid fever, at another an attack of food poisoning. In the present outbreak, although an article of food was infected, apparently of similar nature to the foods which do convey food-poisoning bacilli, the resulting outbreak was paratyphoid fever, and did not show the clinical features of food poisoning. There was some, but not conclusive, evidence that infection originated from an unrecognised human case of paratyphoid fever and the infection bred true. The cases were all of one type, supporting the conception that B. paratyphosus B is a different strain not only serologically but in its aetiological functions from B. aertrycke and other bacteria associated with food poisoning, the one type causing paratyphoid fever only, the latter food-poisoning infections only.

POROKERATOSIS. ACCORDING to Dr. Carroll S. ’right,1 instructor in dermatology and syphilology at the University of Michigan Medical School, who reports an illustrative case in a man aged 40, porokeratosis was first described simultaneously by Mibelli and Resphighi in 1893. Since then not more than 60 cases have been recorded, the condition being particularly rare in the United States. In spite of the numerous theories that have been advanced the aetiology of the condition is still entirely unknown. Heredity undoubtedly plays a part, as was shown by two of Mibelli’s cases, in which a brother and sister were affected, and has since been illustrated by many other cases, including Dr. Wright’s, in which the grandfather, father, and a daughter of the patient were affected. The dermatosis may begin at any age, but, as a rule, it first appears in the earlier years of life. Dr. Wright’s patient had had his lesions since infancy, the father’s lesions had been present throughout life, and the daughter, who was 9 years of age, had had a typical lesion on her leg since infancy. Clinically porokeratosis is characterised by the occurrence of elevated wartlike lesions which, as they enlarge, form an irregular peripheral wall surrounding an atrophic depressed centre. The lesions show a distinct predilection for the hands and feet, genitals, buttocks, and scalp, although they may appear on any site. In a high percentage the mucous membranes are involved. The palms and soles almost invariably escape. Histologically the condition consists first in acanthosis and inflammatory changes in the corium, which are rapidly followed by hyperkeratosis with plugging 1

Archives of Dermatology and

Syphilology, October, 1921.

of the sweat ducts and follicles. except in the cases of individual lesions, which can be removed by excision or carbon dioxide, treatment is ineffectual. According to Dr. Wright, porokeratosis is to be classified under the group of verrucose neevi, because of the wart-like condition of the lesions clinically, the epidermal hypertrophy as observed histologically, the familial tendency, the non-contagiousness, the persistence throughout life, the absence of inflammatory changes, the occasional systematic arrangement, and the failure to undergo involution as the result of X ray treatment.

YAWNING: YAWNING

is

ITS PHYSIOLOGY PSYCHOLOGY.

one

of

those

AND

curiously modified

respiratory acts which has important physiological Mid psychological relations, not the least remarkable of the latter being what might almost be called its "

infectious " nature, associated with imitation on the of the beholder, and which in some people may be excited by thinking intensely of the act itself. C. Mayer in Zeitschrift f. Biologie (vol. Iv., 1921) gives the results of his investigations in man by inspection, laryngoseopy, and X rays. The act itself he divides into three phases : 1. The initial phase, beginning with inspiration, widening of the chest, descent of the diaphragm and larynx until a certain depth of descent of both is reached, elevation of the wings of the nostrils, of the soft palate, drawing of the tongue upwards and backwards, dilatation of the rima glottidis. 2. The acme stage, full dilatation of the thorax to its greatest extent by means of the intercostal and accessory muscles, and descent of the diaphragm and larynx to their lowest position, accompanied by maximum depression of the lower jaw, further retraction of the tongue, and elevation of the soft palate. Tonic contraction of a varying number of individual muscles of the neck, shoulder, and region of the trunk. Wide lateral expansion of the mouth, closing of the eyelids, noise in the ears due to contraction of the tensor tympani, and a subjective feeling of pleasure and satisfaction. 3. Final phase, a short expiration, relaxation of the contracted muscles, ascent of the diaphragm and larynx, and elevation of the lower jaw, secretion of tears, and deglutition. The duration of the tonic contraction of the individual muscles is about 2-46 seconds, that of the whole inspiratory phase (phases 1 and 2) about 5-5 seconds. The biological significance of the acts seems to lie in the energetic ventilation of the lungs. The tonic phenomena accompanying the act can only in part be explained by the irradiation of the inspiratory impulses. This circumstance, along with the accompanying stretching of the arms and extension of the trunk, seem to indicate that the act of yawning and the participation therein of the pronounced contraction of certain muscles is of importance for aiding both the circulation and metabolism. The act itself would seem to be sub-cortical in origin, though it may be excited or discharged by psychical impulses. Spontaneous yawning is an expression of cerebral fatigue and the processes leading up to it stands in intimate relation to the function of sleep. If the optic thalamus is the part of the brain intimately concerned with sleep, then at a certain stage of fatigue the motor impulses for the act of yawning may proceed from it. In certain cases of encephalitis lethargica the execution of the act of yawning may be disturbed and modified.

part

I ’

CLINIC

A

IT is

FOR FUNCTIONAL NERVE CASES.

generally recognisecl

Lnat.

progress

in

anaiyticai

psychology and experience gained during the war have together brought about notable advances in methods of treatment. The Tavistock Clinic for Functional Nerve Cases was opened in September, 1920, in order to bring modern treatment for such conditions within reach of those who cannot afford specialists’ fees, and to act as a centre for the study our