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Infrared spectroscopy and differential scanning calorimetry data are given for the characterisation of three anhydrous and two hydrated crystal modifications of cortisone acetate. All forms revert to the same form on heating to 200°. The amount of hydration estimated from thermal analysis varies from half to one molecule of water per molecule of cortisone acetate. Methods for the preparation of the five forms are described emphasising the importance of solvent composition, particularly its water content. Interconversion of these forms under various conditions such as grinding, contact with water and heat treatment is discussed.

Ionisation constants of several penicillins and of 6-aminopenicillanic acid in water at 25", and approximate ionisation constants of the products of alkaline and penicillinase hydrolysis of some penicillins, are presented. The results suggest that mild alkaline hydrolysis of benzylpenicillin is not a simple reaction. The initial product (the penicilloic acid) has the same imino-group ionisation constant as the product of penicillinase hydrolysis, but this ionisation constant decreases after further treatment with alkali. The nature of this effect is discussed.

Glycine can be made by electro‐reduction of glyoxylic oxime which may either be used as the starting material, or be prepared in situ by reaction of glyoxylic acid with hydroxylamine. These two compounds are made in the same cell by electro‐reduction of oxalic acid and nitric acid. Thus when glycine is made from glyoxylic oxime prepared in situ, three reductions take place at the same electrode. This process, which gives a good yield of glycine, is discussed, and an account is given of the experimental technique and analytical methods used. The current efficiencies for the three reductions appear to be adversely affected when they are carried out simultaneously and at the same electrode.