222 sustain an increase of its metabolism. If the metabolic rate of the tissues is raised but sufficient fuel is not forthcoming, the tissues will die and fresh gangrene will result. These arguments are theoretical, but are supported by some interesting animal experiments by Allenin America. He found that if a rabbit’s limb was strangulated with a tourniquet and immersed in ice-water for as long as 52 hours it would still recover, whereas a limb strangulated at room temperature would survive for only about 15 hours. If the limb was artificially warmed to 38° or 39° C. it would be even more rapidly affected by the strangulation. Moreover, the general toxic effects after release of the tourniquet varied inversely with the temperature of the limb during strangulation. It is a pity that Allen’s experiments were not more strictly controlled, but he has at least made out a good case for further investigation. Clinical tests should also be carried out. It may be that a radical change will have to be made in the management of the gangrenous limb ; perhaps it should not be warmed, but cooled. ITCHING
IRRITATION of the skin
by slight burns, freezing,
ultraviolet irradiation produces two kinds of itching, named by Bickford2 "spontaneous itching" (at the point of irritation) and " itchy skin " (in an elliptical area surrounding the point of irritation and evoked by the stimulus of touch). There is a definite boundary between itchy and normal skin. Injections of a solution of histamine in normal saline showed after puncture a latent period of 20-30 sec. before spontaneous itching began. Itchy skin could usually be detected over a small area in the immediate vicinity of the puncture at the end of a minute, and during the next 10 minutes it extended to form an elliptical area whose long axis was always parallel to the cutaneous nerve-trunk of the same region. That this phenomenon was not due to the diffusion of histamine was proved by injecting histamine into an anesthetised area, whereupon itchy skin did not develop until the local anaesthesia had passed off. Experiments were made to determine the nervous pathway. Reflex action through the spinal cord was excluded by the type of cutaneous response in the presence of barriers of anaesthetised skin. Itchy skin developed at a normal rate on the proximal side of such a barrier but was delayed on the distal side until the anaesthesia had passed off. This proved that the nervous pathway was local, and the fact that itchy skin did not spread round the edges of the barrier suggests a plexiform arrangement of the local nerves rather than a freely anastomosing network. The sympathetic nervous system was excluded from the mechanism of itchy skin by experiments in patients who had undergone unilateral sympathectomy. It was also found that itchy skin could be abolished by a degree of asphyxia that did not affect spontaneous itching. This showed that the two sensations were carried by different nerves. The sensation of tickling is closely associated with that of itchy skin. In cases of sensory dissociation itchy skin is not detected in areas that have lost the sensation of tickling, even though the sensation of touch may be retained. Spontaneous itching is not felt where pain to pinprick is defective. Tickle sensation, spontaneous itching, .and itchy skin are all conveyed in the anterolateral tract and disappear when it is divided. Itchy skin can be inhibited (the inhibition being of central
F. M., 1 Allen, 2 Bickford,
Surg. Gynec. Obstet. December, 1938, p. 746. R. G., Clin. Sci. December, 1938, p. 377.
and probably produced through pain nerves), shown in " antipruritic " skin produced by painful stimuli.
SPONTANEOUS hyperventilation is admittedly a not manifestation of excitement, anxiety, and Since it was first emotion in unstable people. described in 1922 numerous cases have been recorded, originating from a great variety of exciting stimulisome of them bizarre. Almost always the presenting symptom has been tetany or hyperventilation, and there has been no doubt of the diagnosis. It is of course certain that many cases will have escaped recognition ; but if Soley and Shockare correct in supposing that " effort syndrome," which has been well known for a long time, is really nothing more or less than spontaneous hyperventilation, there will be little to be said for those who have made a study of effort syndrome. There are, however, one or two points about Soley and Shock’s contention that deserve critical reflection. Effort syndrome attacks both sexes, whereas hyperventilation tetany is rarely met with in men. (The only case described by Soley and Shock was in a woman.) Furthermore, effort syndrome is not characterised by tetany, which is usually a feature of simple hyperventilation. No doubt these discrepancies will be investigated but meantime there does not seem to be enough evidence to discard the old terminology of effort syndrome (as Soley and Shock suggest) and to substitute an "anxiety state complicated by the hyperventilation uncommon
syndrome." NATIONAL NUTRITION POLICIES
Too little attention is paid to the non-political work of the League of Nations. The technical commission on nutrition, for example, has been trying to help governments all over the world to improve the2 physical state of their peoples, and its latest report describes the policies that various governments have actually adopted. It will be seen that some countries have done a good deal and others very little, but it is encouraging to observe the thoroughness with which some nations at least are investigating their problems. The national nutrition committees working under the League not only give advice to their governments but sometimes make recommendations on their own initiative. In 1937, for instance, the Danish committee drafted a bill to compel the proper preparation of flour, and the Iraq committee has advised its government on measures for stimulating fisheries. In many countries measures have been taken to remedy deficiencies in the dietary of the poor, especially the lack of milk. In Latvia the cooperative dairies offer bonuses to milk-producers, and in Norway grants are made for the provision of cheap milk, meat, and bacon to poor families. Many countries provide meals free or cheaply to special groups of consumers. Diet schedules have been drawn up and supervised by national nutrition committees on behalf of public institutions in which food is ’provided by the authorities. The League recognises, however, that ultimately the obstacles to sound nutrition are largely economic, and that measures of public assistance scarcely touch the edge of them. Other measures adopted by different countries are the reorganisation of agri1 Soley, M. H., and Shock, N. W., Amer. J. med. Sci. December, 1938, p. 840. 2 Survey of National Nutrition Policies. League of Nations. 1937-38. Allen and Unwin. Pp. 120. 2s. 6d.