The object of this communication is to prove finally that the nervous symptoms in vitamin Bj deficiency and the change in oxidative behaviour of pigeon's brain tissue are intimately related and are entirely independent of loss of weight, or general inanition. Previous work (Gavrilescu and Peters, 1931) had shown that the brains or tissues of birds after complete cure had a normal oxidative behaviour in glucose-phosphate solutions, at a time when no increase in weight had taken place. This left

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... ittle escape from the conclusion that the symptoms were not due to the inanition. Nevertheless, the point was felt to be so important that further proof wT as desirable, with even more rigorous control. An opportunity for this wT as presented by the recent discovery (Gavrilescu, Meiklejohn, Passmore and Peters, 1932) of the essential importance of lactate rather than glucose, and of the large in vitro effect of vitamin Bx concentrates. Accordingly, we have followed the oxygen uptakes in lactate solutions of the brains of pigeons which have been cured of opis thotonus symptoms by dosing with vitamin Bx concentrates. A marked increase in the oxygen uptake has been found corresponding with the dis appearance of the nervous symptoms, and the restoration is accompanied by a decrease in the effect of the concentrates in vitro. Methods.-These have been as previously described, and the figures quoted in the tables are calculated from the oxygen uptakes at 38° C. of 50-100 mg. of the minced brain tissue, suspended in 3 *0 c.c. lactate-phosphate solution. The vitamin Bx concentrate had an activity for the bird of approximately 0 • 05 mg.,! and the same concentrate was used throughout, both to cure and in the bottles in vitro. The vitamin Bx concentrates have been given both orally and intramuscularly ; symptoms usually disappear within 3 hours in the former case, and 1 hour in the latter. No food was given after dosing, and the * Senior Demy of Magdalen College. t Senior Scholar of Brasenose College. X Pigeon day don.