Clinical Evidence relating to Hyperthyroidism 39 



poisonous effects of acetonitrile ; an effect he had previously found to 

 result from injection of thyroid extract. Some observers have stated that 

 injection of blood-serum from cases of exophthalmic goitre produces effects 

 in animals similar to the symptoms of that disease in man. Others, on the 

 contrary, have obtained different results, and state that, although in dogs 

 small doses of extract from an exophthalmic goitre may cause increased 

 rate of heart-beat and some rise of blood-pressure, this is soon followed 

 by the opposite condition. They therefore hold that the symptoms are 

 produced not by excess of normal thyroid secretion circulating in the blood, 

 but as the result of the production of a perverted secretion (dysthyroidism). 

 This view is not, however, that generally taken, either by physiologists or 

 clinicians, most of whom are disposed to regard the hypersecretion theory as 

 more probable. The favourable results which ensue in many cases from 

 surgical removal of a large portion of the hypertrophied gland or ligature 

 of some of its vessels point in that direction. 



