Kinetic data for the hydrolysis of potassium pacetylphenyl sulphate by fresh rat liver suspensions suggested that the arylsulphatase activity so observed could be attributed to a single enzyme (Dodgson, Spencer & Thomas, 1953) which was later found to be localized mainly in the microsomes of the liver cell (Dodgson, Spencer & Thomas, 1954a). Preliminary attempts to purify the microsome enzyme (unpublished data) were handicapped by its insolubility in various buffers and salt solutions of widely differing pH even after treatment of the liver by acetone-drying, alternate freezing and thawing, or use of the tissue disintegrator (Mickle, 1948). Sulphate and phosphate ions had little effect on the enzyme. These results contrast sharply with the arylsulphatase pattern reported for ox liver (Roy, 1953a, b; 1954). Using dipotassium 2-hydroxy-5nitrophenyl sulphate as the assay substrate, Roy was able to separate two arylsulphatases from the soluble material of acetone-dried ox liver and both enzymes were strongly inhibited by sulphate and phosphate ions. With the same substrate the arylsulphatase activity of mouse liver was found to be mainly concentrated in the mitochondria (Roy, 1953a). The present work, a preliminary report of which has already appeared (Dodgson, Spencer & Thomas, 1954 b), shows how the occurrence of three different arylsulphatases in mammalian livers enables these contrasting findings to be reconciled. METHODS Arylsulphates. Potassium p-acetylphenyl sulphate (APS) and potassium p-nitrophenyl sulphate (NPS) were prepared by the method of Burkhardt & Lapworth (1926) and dipotassium 2-hydroxy-5-nitrophenyl sulphate (nitrocatechol sulphate, NCS) according to Roy (1953a). Measurement of arylnulphata8e activity. The method previously used for APS (Dodgson, Lewis & Spencer, 1953) was also adopted for NPS but using the Am.. and e,,. determined for p-nitrophenol (Dodgson & Spencer, 1953). The use of NPS was restricted to liver extracts, as recoveries of p-nitrophenol from fresh liver suspensions are low (Dodgson & Spencer, 1953). The faint turbidity of the final solutions was the same in both test and controls and duplicate determinations were satisfactory. Turbidity only inter

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In the female rat intoxicated with ethylene glycol the oxaluria increases with the degree of intoxication. The increase is less in the animals treated with succinimide. The comparative study of the results of the dosages made with gas-liquid-chromatography and by various colorimetric methods show that this later gives varying results and underestimates high concentrations of oxalic acid. The result is that any study based on results of dosages of urinary oxalic acid made by colorimetry must be taken with some reserve, and this on whether the oxalic lithiasis is experimentally induced or human, or whether its evolution is spontaneous or influenced by a therapeutic.