THE SYMPATHETIC SYSTEM 87 



hypertrophy obtained experimentally after the removal of 

 the greater part of the thyroid and show definitely a hyper- 

 function of the gland: hypertrophy and parynchymatous 

 hyperplasia with increased colloid secretion. The colloid 

 is paler, less chromophilic and more friable than normally. 

 The abnormal cellular proliferation is characterized by 

 masses of eosinophils. The thyroid follicles are dilated 

 and are shown surrounded by fibrous tissue, more or less 

 abundant and containing lymphoid cells. 



Lesions of the cervical sympathetic are rare. In some 

 cases the nerves are increased in volume and sclerosed ; the 

 inferior cervical ganglion contains atrophic cells, smothered 

 by a proliferation of connective tissue. 



Lesions of the nervous system (bulb and cord) are ex- 

 ceptional and when they do exist do not have any spe- 

 cific appearance. 



It is quite common to see an increased activity of the 

 thymus in cases of exophthalmic goitre. 1 



PATHOGENESIS. 



In spite of numerous theories, the definite pathogenesis 

 of Basedow's disease is still undetermined. 



1. NERVOUS THEORY. The syndrome is produced by 

 a lesion of the cervical sympathetic (Abadie). The 

 stimulation of the sympathetic causes tachycardia, ex- 

 ophthalmos, dilatation of the arteries of the thyroid. 

 Secondarily, the thyroid hypertrophies and due to a 

 functional hyperactivity, pours into the blood stream 

 toxic substances which cause the secondary symptoms: 

 tremor, diarrhea, loss of weight, etc. 



2. THYROID THEORY. (a) Hyperthyroidism. Base- 

 dow's disease is the result of a hyperthyroidism (theory of 

 Moebius). Experimental, clinical and therapeutic obser- 



1 This may account for the ovarian and genital atrophy. 



