DYSTHYROIDISM 113 



thyroid physiology. This we do not possess. Great 

 strides have been made in this direction. Thyroxin 

 recently has been isolated by Kendall, but the functions 

 of this active principle, other than that it is a stimula- 

 tor of metabolism, are yet to be revealed. The probable 

 existence of other hormones is not disproven nor does 

 the discovery of thyroxin throw much light on the 

 pathologic physiology of the thyroid. McCaskey 1 has 

 interpreted this discovery as firmly establishing the 

 theory of hyper- and hypo-secretory types of the thy- 

 roid functioning, and leaving "no chance for a claim of 

 dysthyroidism." He fails, however, to explain satisfac- 

 torily the presence of some of the symptoms of so-called 

 exophthalmic goitre in a cretin. 



Other undeniable clinical facts, which are contradic- 

 tory in the theory of hyperthyroidism, fit in quite well 

 with a theory of dysthyroidism which Janney 2 has very 

 ably advanced and in favor of which has adduced much 

 evidence. Sclerodermia, 3 keratoconus, 4 episcleritis, and 

 localized trophic disturbances, especially of the eye, 

 which are benefited or cured by thyroid extract, sup- 

 port the theory of dysfunction, especially when they 

 occur in cases of both hyper- and hypothyroidism, so- 

 called. 



The little knowledge which we possess concerning 

 the causes of dysthyroidism has elucidated the problems 

 only slightly. Nervous shock, infections, puberty and 

 the menopause are only indirect causes and do not in 

 all individuals produce thyroid dysfunction. The ulti- 

 mate, direct cause is still to be ascertained. Who shall 

 discover it, the physiologist, the pathologist, the surgeon 

 or the clinician ? 



Most of our information regarding thyroid conditions 

 has been obtained by surgeons, and the whole subject 

 is viewed very largely from a surgical aspect. The 

 habit of resorting to surgical measures as soon as the 

 diagnosis is made has become so widespread that the 



