ENDOCRINE GLANDS 393 



The thyroid. It has been found that undersecretion of the 

 thyroid gland is responsible for the condition known as cretinism, 1 

 and that this condition can be improved and frequently completely 

 cured by supplying the patient with thyroid secretion, usually 

 by feeding with thyroid extract. Overactivity of this gland 

 produces exophthalmic 2 goiter, a condition of extreme nervousness, 

 with loss of weight and other symptoms, such as protruding eye- 

 balls and irregular heart action. 



In some parts of the country where the water supply comes 

 from mountain sources many people are troubled with a slight 

 enlargement of the thyroid gland. This trouble comes from a lack 

 of iodine in the water supply. This iodine deficiency in the water 

 can usually be corrected by eating foods rich in iodine, such as 

 sea foods and certain vegetables, or by putting iodine in the 

 drinking water. 



The adrenal glands. The adrenal glands produce a secretion, 

 adrenin, which acts upon the muscles and the nervous system. 

 It causes a faster beating of the heart, a heightened blood pressure, 

 and other indications of increased muscular activity. It is indeed 

 the emergency hormone of the body. It is this hormone that 

 enables the sprinter to make his final burst of speed at the tape, 

 or the football player to make a desperate stand when almost 

 exhausted. It explains the " strength of desperation." Adrenin 

 has been prepared in the laboratory and is known commercially 

 as adrenaline (ad-re'nal-in) . It is used in medicine to contract 

 the blood vessels, hasten the clotting of blood, and to strengthen 

 the heart beat. 



The pituitary and thymus glands. The pituitary gland has much 

 to do with body size. Dwarfs appear to lack or have very small 

 pituitary glands, while giants always have abnormally large ones. 

 Dr. Harvey Cushing of the Harvard Medical School, who is an 

 authority on the work of the pituitary body, says : " The Lewis 

 Carroll of today would have Alice nibble from a pituitary mush- 

 room in her left hand and a lutein (a pigment obtained from a 



1 Cretinism (kre'tin-izm) : idiocy accompanied by physical deformity. 



2 Exophthalmic (ek'sof-thal'mik) : pertaining to a disease causing protrusion of 

 eyeballs. 



