The reduction of glutathione by plant tissues.

as far as possible. The precautions described above have been found to be necessary in order to achieve this. It was thought at first that a certain amount of hydrogen chloride, as well as carbon dioxide, would diffuse into the alkali. Accordingly, ION-phosphoric acid was tried instead of hydrochloric acid, but this did not liberate all the carbon dioxide, even after heating for 24 hr. at 1500. Sulphuric and benzenesulphonic acids were also tried, but both gave high and variable yields, probably through their acting as oxidants. Sodium hydroxide was tried in the buckets instead of barium hydroxide, the carbon dioxide being estimated by the difference of titres with acid to the phenolphthalein and methyl orange end points. Finally, by use ofthe titrimetric method of Sendroy (1937) to estimate chloride, it was found that no detectable amount of hydrochloric acid was reaching the barium hydroxide. Diffusion for periods greater than 2 hr. was found to be undesirable, because ofa gradual increase ofthe blank titre. In confirmation of the work of Tracey (1948), 5 hr. heating with acid was found to liberate all the carbon dioxide from citrus pectin, acetone glucurone and from hyaluronic acid. The yield from methyl galacturonide was incomplete in this period.