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' 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? has very 
ably advanced and in favor of which has adduced much 
evidence. Sclerodermia,* keratoconus,‘ 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 
