Heating of the whole body by immersion in water for short periods (Vernon, 1924) or of a limb by application of hot fomentations (Hall, Schamp, Brown & Davis, 1944; Hall, Munoz & Fitch, 1947) has been shown to reduce the strength and duration of voluntary rhythmic and sustained contractions. More recently, Nukada & Muller (1955) and Nukada (1955) showed that when a limb was immersed for a short period in water ranging from 10 to 400 C (rhythmic contractions) and from 20 to 400 C (sustained contractions) the duration of contractions to fatigue steadily increased from the higher to the lower water temperatures. These experiments on human subjects have led all these observers to the conclusion that the influence of temperature on the performance of muscular contraction is due to alterations in the proportion of blood flowing through the muscle and the skin of the exercised limb.The possibility that the temperature of the muscle might be associated with the duration or strength of contraction has been dismissed by these workers, but the evidence of Ellis & Beckett (1954) and Hadju (1951) casts some doubt on the validity of such a conclusion. Working with isolated muscle preparations, they showed that both strength and duration of contractions, in the absence of a blood supply, depend on muscle temperatures.Lind & Samueloff (1957) measured in man the duration of successive sustained contractions when the interval between the contractions was varied and when the arm was kept in water at 18 or 340 C throughout the experiment. They found that contractions were always longer in water at 180 C when the interval between contractions was 20 or 40 min.The present experiments were designed to discover (a) whether there was a further deterioration in muscular performance when the forearm was heated in water above 340 C, and (b) if further improvement occurred in the strength and duration of contractions when the water was cooler than 180 C. Blood flow, muscle temperatures and action potentials were measured on the exercised

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We have studied the effect of age on washin of isoflurane and halothane by comparing end-tidal (PE') and arterial (Pa) partial pressures of the agents in young (18-32 yr) and elderly (63-82 yr) healthy patients for 20 min after introduction of the agents, before surgery. PE' was measured by infra-red analysis and Pa by gas chromatography. Washin of isoflurane occurred at the same rate in the young and elderly, with no significant difference between young and elderly in PE' or Pa as proportions of the inspired partial pressure (PI). After 20 min of isoflurane administration, mean Pa/PI in the young was 0.57 (95% confidence limit (CL) 0.53-0.62) and 0.55 in the elderly (95% CL 0.51-0.59). Washin of halothane was slower in the elderly than in the young, with Pa/PI significantly less in the elderly from 10 min after introduction of halothane. The difference between age groups, however, was small: mean Pa/PI after 20 min of halothane administration 0.45 (95% CL 0.41-0.49) in the young and 0.38 (95% CL 0.35-0.41) in the elderly. Washin of isoflurane was significantly faster than that of halothane in both young and elderly subjects. For isoflurane, the PE'-Pa gradient was small relative to Pa and did not differ significantly between young and elderly. For halothane, PE'-Pa in the young did not differ significantly from that for isoflurane. In the elderly, PE'-Pa for halothane was significantly greater than in the young and than PE'-Pa for isoflurane.

Liver function tests carried out after minor surgical procedures, under anaesthesia lasting for 1 hr, showed no abnormalities. Tests after body surface operations under the same anaesthetic techniques showed transient derangements. After intra-abdominal procedures, liver dysfunction was more marked, although no patients with evidence of preoperative liver dysfunction or postoperative surgical complications were studied and none received blood transfusions. Measurements of the serum bilirubin concentration showed the most frequent abnormalities, but the pseudocholinesterase concentration decreased progressively after intra-abdominal surgery and b.s.p. retention increased significantly. Serum concentration of intracellular enzymes (LDH, s.g.o.t. and s.g.p.t.) increased within an hour of starting surgery, changes which were probably not related to liver function.