During the past eight years Plummer has been making an extended clinical study of thyroid disturbances in several thousand cases of hyperplastic and colloid goiters, and has gradually formulated the following basic hypotheses:
In thyroid disturbances the effects are due to a change in the rate of a normal function.
The stimulating effect of increased thyroid activity is not felt in any particular set of organs or tissues alone, but the stimulus is active throughout the body.
The stimulating action is intracellular.
I wish at this time to draw attention to these fundamental aspects of thyroid disturbances, since they were formulated prior to the work reported herein, and any theory of the function of the thyroid should at least fulfil the conditions Plummer outlines.
Several months ago I reported the isolation from the thyroid of a crystalline substance containing 60 per cent, of iodin and possessing the physiologic activity attributed