Exophthalmic goiter is usually regarded as a disease dependent on increased or perverted secretion of the thyroid gland. This conception is supported by several facts, among them, that partial removal of the enlarged thyroid not uncommonly serves to mitigate the severity of symptoms, while the administration of thyroid extract intensifies those symptoms which are already present or brings out fresh disturbances of various sorts. Confirmation is also to be had in the fact that the prolonged administration of thyroid extract to dogs and monkeys results in exophthalmos, increased rapidity of the pulse, changes in nitrogenous metabolism, loss of weight and sweating. However true this may be, there are equally good reasons for the belief that alterations in the activity of the thyroid gland are not wholly responsible for the multiplicity of symptoms in exophthalmic goiter, but that other influences are active, such as disturbances in the sympathetic system and, possibly,