Hypothermia was used some 20 years ago in the treatment of malignant tumours. During the last decade it has also been found useful in operations on the heart and on the brain. Methods now available for lowering the body temperature are regarded as safe. Nevertheless, some questions call for further investigation, such as: Does hypothermia produce morphological tissue changes?Microscopical changes after hypothermia have been observed in organs from various animals, but opinions differ in respect to both the extent and severity of the changes, and some authors even deny the occurrance of such changes.Artificial hypothermia, i.e. relatively rapid lowering of the general body temperature of anaesthetised human beings, found increasingly wide use after the fundamental investigations by Bigelow ( 1 ) . The microscopical changes described in these cases of hypothermia vary widely. Some authors, for example, found a n extracellular accumulation of fluid in different organs and degenerative changes and accumulation of inflammatory cells. Some investigators such as Sarajas ( 1 3 ) and Knocker ( 7 ) claim that these changes, a t least in dogs, are severe even if the organism is not cooled for any length of time, and even if the reduction in temperature is only small. On the other hand, other authors have not found any changes a t all or a t most slight changes (3, 6 ) . M A T E R I A L A N D M E T H O DNineteen full-grown rahhits were used. The animals anaesthetised with allylisohutylmalonylthiocarhamidesodium (Baytinal, Bayer) and afterwards cooled in a refrigerator ( 2 ) to $28" C. The temperature was maintained as steady as possihle at this level. Six rabbits were cooled for 48 hours, 2 for 34 and 2 for 38 and the remainder for 2-3 hours. Artificial respiration was not induced. The animals were killed immediately after the experiment. After careful gross inspection various organs (heart, liver, spleen, lungs and kidneys) were removed and fixed in 1 0 per cent formalin. 151

This is the first case, hitherto described, of benign essential gammopathy, presenting symptoms and histological evidence of peripheral neuropathy. Furthermore, in no previous case, has a specific localization of immunoglobulin (type IgM) to the areas of nerves involved by the lymphocytes been demonstrated. After six months' treatment with chlorambucil the neurological symptoms disappeared and in a biopsy from the right n saphenus no endoneural lymphocytes or local IgM could be found.

This article deals with the presentation of a 47-year-old male patient with total absence of the solid wall of the right ventricle but not of the trabeculae carneae or of the papillary muscles. The previous history included attacks of paroxysmal tachycardia and, furthermore, angina of effort during the last three years. The terminal events were dominated by several types of arrhythmias. The autopic findings revealed no degenerative or inflammatory changes of the myocardium. The coronary arteries were normal except for non-contributory minimal atheromatous deposits. Absence of the solid part of the right ventricular musculature probably represents a congenital defect. A . R., Adaro, F. V . M., Roncoroni, A. J.: Idiopathic myocardiopathy resulting in failure of contractility of the right ventricle. Am. J. Med. 48: 235-238, 1970. Viola,de Vries, P. A . & de C. M . Saunders, I. B.: Development of the ventricles and spiral outflow tract in the human heart. Contribs. Embryol. 37: 87-114, 1962.