The Rôle of Thyroid and of Diet in the Acetonitrile Test *

Since the announcement by Hunt in 1905 of a new effect of thyroid substance in protecting mice against acetonitrile poisoning, interest has centered upon this problem. Basing his opinion on a long series of experiments, Hunt, in his original and subsequent papers, reported that the test was a sensitive and specific one for thyroid substance, and that the degree of protection afforded to mice by different samples of thyroid, within minimum and maximum limits, paralleled their iodine content. This, and the proportional clinical potency of his various thyroid specimens, led him to doubt the presence of physiologically inactive iodine in the gland. More recent experiments of Marine and Williams, of Miura, of Morch, and especially those of Harington and Randall demonstrating the presence of inactive di-iodotyrosine in thyroid, make Hunt's conclusion improbable, but do not lessen the possible value of the test he describes. It was hoped that the phenomenon of protection might supply a delicate and specific test for the active component of the thyroid; that it might be relied upon to detect thyroid substance in the blood of patients (Hunt, 1907; Salomon; Carlson and Woelfel; Ghedini; Oehme and Paal) and in proprietary drugs (Hunt, 1925); and that it might be used as a rapid, quantitative test for the presence of the active substance during attempts at isolation. But difficulties soon arose. Hunt asserted that the test was easily reproduced, both qualitatively and quantitatively, but other workers did not find it so (Paal, Gellhorn, Carlson, Trendelenburg). In the experiments described in the original papers the use of different diets was attended by widely varying resistances of mice to acetonitrile without the addition of thyroid. Even when the basal diet was maintained strictly unchanged, the survival dose of the