Thyroid and Temperature in Cold-blooded Vertebrates

THE thyroid is well known to be concerned with temperature regulation in homothermic animals. It seems, however, also to have a somewhat analogous function in cold-blooded forms. In an experiment undertaken to investigate the temperature coefficient of metamorphosis, a number of sets of half-grown Rana temporaria tadpoles, after all being exposed to the same concentration of filtered thyroid suspension in water for the same length of time, were placed at various temperatures from 3° to 30° C. The thyroid dosage was moderate, sufficient to produce metamorphosis in about a week at room temperature