2
Some have regarded the sympathetic system as at fault, on account of the character of many of the nervous symptoms and because a slight exophthalmos can be produced by stimulation of the sympathetic. There is, however no anatomical basis for this theory, for the changes which have been described in the sympathetic are only those which may occur in health or in other diseases.
There is much more evidence to support the view that exophthalmic goître is due to some primary lesion of the medulla. Thus Filehne[1] found that section of the anterior fourth of the grey matter of the restiform bodies was followed by exophthalmos. In some of his experiments both enlargement of the thyroid gland and exophthalmos occurred, and in one case tachycardia as well. Bienfait[2] made bilateral transverse sections through the grey matter of both restiform bodies in rabbits. This was followed by marked alteration in the cardiac rhythm and a fine regular tremor. Exophthalmos was present in rather more than one-third of the animals used, and in one-fourth of them distinct hyperæmia of the thyroid gland appeared. These experiments show that some of the symptoms of exophthalmic goître may occur as a result of interference with the normal action of the nerve centres in the medulla. In connection with these experiments an interesting case mentioned by Mannheim[3] may be referred to in which exophthalmic goître developed a few days after the onset of a bulbar hæmorrhage and improved as absorption of the blood-clot took place.
The medulla has been carefully examined in a considerable number of cases of exophthalmic goître and in some cases definite changes have been found. Thus subserous hæmorrhages were found on the surface of the floor of the fourth ventricle by Bruhl and by Lasvènes. Numerous hæmorrhages were found by Hale White in the medulla of one case; they have also been found by other observers. It is very doubtful if these small hæmorrhages are of any pathological importance, as they are not infrequently found in cases in which no symptoms of exophthalmic goître have occurred. Mendel found atrophy of the left restiform body and of the right "solitary bundle." On the other hand, Müller and others have found no signs of disease of this part of the nervous system in the cases examined by them, and Möbius states that as a rule no lesion of the medulla is found. It is thus evident that the changes which have been described are by no means constant, and so we cannot regard them as the cause of the disease.
The thyroid gland is more obviously diseased than any organ in the body of a person suffering from exophthalmic goître, and I know of no case on record in which it has been found to be normal in structure when examined after death. We shall briefly consider the changes in structure which are found and compare them with other morbid changes, the results of which are well known. Let us compare the normal gland first with one which has been rendered almost functionless by extensive fibrosis, then with one which has undergone compensatory hypertrophy, and so is in a condition of unusual activity, and finally with a gland removed from a patient suffering from exophthalmic goître.
The normal gland is composed of a number of closed follicles
