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THE development of a technique utilising the short acting relaxant suxamethonium chloride (succinyldicholine chloride, Scoline) and the analgesic lignocaine hydrochloride (Xylocaine) followed the successful use of the combination gallamine and thi0pentone.l Scoline is an ultra short acting relaxant, and the length of action of a single dose appears to be intimately related to the level of serum cholinesterase of the recipient.2 3 4The administration of scoline by continuous intravenous drip was first described by Thesleff and von Dardel5 who used a 0.1 % solution. Green5 in a recent publication used a similar technique but in larger dosage and with controlled or aided respirations. Xylocaine, w-diethylamino-2-6 dimethyl-acetanilide, a tertiary arnine of high stability, was synthesised by Lofgren in 1943.7The absolute toxicity of xylocaine must be concluded to be slightly greater than procaine from the work by Goldberg,S who demonstrated that in concentrations of more than 0.5 % given subcutaneously in mice the toxicity was greater than procaine, and paradoxically in concentrations of less than 0.5 % equal or less than procaine.In a report by Richard Gilbert et a19 using intravenous xylocaine in obstetrics, the only toxicity witnessed transpired after prolonged and rapid administration. These untoward effects, tinnitus, facial twitchings and ankle clonus, disappeared as soon as the rate of administration was slowed. In our preliminary trials with a xylocaine drip, a case showed twitchings of the face followed by generalised convulsions, when the rate of administration was at a fast drip rate (80 dropdmin. for 15 mins.). These manifestations rapidly disappeared on cessation of the drip, and did not reappear when the drip wac recommenced at a slower rate.The marriage of scoline and xylocaine developed in the search of an equivalent to the mixture gallamine and thiopentone.The resulting hydrolysis of scoline in the presence of the alkalinity of thiopentone precluded the use of this combination. Intermittent 96

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