1240 



PHYSIOLOGY 



is indeed one of the therapeutic triumphs of the last twenty years. An ugly 

 and idiotic cretin can be converted by this means into a child of ordinary 

 intelligence with normal powers of growth (Fig. 560). Given to myxcedemic 

 patients, the thyroid gland reduces the swelling of the subcutaneous tissues, 

 causes a new growth of hair, and restores the patient to his or her former 

 state of mental health. Nor is the thyroid gland without influence on the 

 healthy individual. If given in large doses either to man or animals, it 

 quickens the pulse, even causing violent palpitation, and increases the meta- 

 bolic activities of the body, so that the appetite is increased, the nitrogenous 

 output rises above the intake, and the subcutaneous fat is diminished or 



A B C 



FIG. 560. A, a cretin, 23 months old. B, the same cliild, 34 months old, after ad- 

 ministration of sheep's thyroids for 11 months, c, a cretin, untreated, 15 years 

 old. (W. OSLEE.) 



disappears. It is possible that a moderate degree of thyroid inadequacy is 

 not infrequent and that the beneficial effects on general health, in removing 

 excessive corpulence and in promoting the growth of hair, which are observed 

 on administering the drug to people of middle life, may be due to the 

 actual replacement of a function which is being insufficiently discharged. 

 The symptoms caused by excessive doses of thyroid gland are strikingly 

 similar to those occurring in the disease known as exophthalmic goitre, 

 where there is a true hypertrophy of the gland associated with can liar 

 palpitation, proptosifl (bulging of the eyes), wasting, and muscular weakness. 

 All these facts warrant us in including the. thyroid body among the 

 glands with an internal secretion, t lie presence of which in the blood stream 

 is a necessary condition for the normal mmvili and functions of almost all 

 the tissues of the body. If this secretion is lacking we obtain the condition 

 known as myxoedema in adults, as cretinism in young children. If it be 



