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The major excretory metabolite of thyroxine in the insect Corcyra cephalonicaSt. is iodide, though monoiodotyrosine and di-iodotyrosine are present in small amounts. In vitroexperiments with homogenates of larval tissue have shown that an enzyme system capable of forming iodide from thyroxine is present only in tissues of larvae fed thyroxine-supplemented diets and not in those of larvae fed control diet alone. Activity of the enzyme is destroyed by boiling for 10-15 minutes.

The inclusion of arachidoside and anacardioside, the pigments isolated from the outer skin-covering of groundnuts and cashewnuts respectively, in the diet of rats, at a level of 20 mg per rat per day for 7 weeks results in goitre. Incorporation of potassium iodide in the diet counteracts partially the goitrogenic action of the anthocyanins. Results of studies on the distribution of radioactive iodine in the thyroid glands of the rats suggest that the pigments inhibit the organic binding of radioactive iodine.

CONTINUED daily injections of β-hydroxy butyrate in gradually increasing doses has been found to increase initially the insulin content of the pancreases of guinea pigs and then bring about a gradual decrease of active insulin/gm. of pancreas tissue1. Similar experiments by Schwartz et al.2have recently confirmed these findings in both guinea pigs and albino-rats. The present communication indicates the effects of some members of the trichloroacetic acid cycle, compared to β-hydroxy butyrate, on the insulin response of normal rabbits.