194 DUCTLESS GLANDS 



of the body, and the aforementioned results disappeared, although 

 the effect of the grafted thyroids were only temporary. Extracts 

 of the thyroid tissue are now given to persons whose glands do 

 not function properly. In most cases the treatment is successful. 



Thyroxin probably has some effect upon growth and develop- 

 ment of organisms. Gudernatch, while teaching at Columbia 

 University, has carried on a series of interesting experiments on 

 glandular feeding. He fed thyroid glands (of different animals) 

 to very young tadpoles and they promptly went through meta- 

 morphosis and became frogs. In some cases the frogs were no 

 larger than a beetle. When he removed the thyroid gland from 

 other tadpoles, they never became frogs, although they grew larger 

 than the usual size of a tadpole. 



Thyroid deficiency, due to degeneration or an operative removal 

 of the glands, in an adult- gives rise to dullness and general 

 apathy or sluggishness. The person gets very stout, although his 

 appetite may be diminished. The heart beats slower, the nervous 

 system becomes sluggish, and the general intelligence is lowered. 

 This condition is easily explained by the slow rate of oxidation. 

 The disease is called myxedema. If in a young child the thyroid 

 glands waste away, his head and face usually become enlarged, and 

 look deformed, and his abdomen becomes swollen. The mental 

 faculties as w-ell as the physical character of these sufferers show 

 lack of development and often lead to a condition of idiocy. This 

 disease is called cretinism, and children suffering from it are called 

 cretins. When thyroid extract is fed to persons suffering from 

 myxedema or cretinism, they usually improve and sometimes are 

 completely cured, provided no essential organs have been affected. 

 This thyroid treatment must, however, be kept up indefinitely 

 because the patients' glands are atrophied and will remain inactive. 



In some communities, a large percentage of the population shows 

 an enlargement of the thyroid glands ; this condition is known as 

 endemic goiter. It is common in certain sections of our country. 



