130 THE INDIVIDUAL ORGANISM 



and failure to develop sexually. Cures that can only be described as amazing are 

 obtained by feeding thyroids to cretins. Deficiency in the adult causes myxedema, 

 a condition of lowered metabolism accompanied by puffy swelling of parts of the 

 body, especially the hands and face, and by sluggish physical and mental func- 

 tioning. Excessive activity of the thyroid, on the other hand, results in a marked 

 increase in oxidative metabolism, with loss of weight. Both figuratively and liter- 

 ally the individual is burning himself up. 1 Such hyperthyroidism is accompanied 

 by nervous disorders, restlessness and great excitability, high heart rate, derange- 

 ment of reproductive functions in women, and protruding eyeballs. It can be 

 alleviated or cured by removal of part of the thyroid or by tying off some of the 

 arteries supplying it. Some forms of goiter are caused by deficiency of iodine in 

 the diet, but exophthalmic goiter results from enlargement and hyperactivity of 

 the thyroid, resulting from overproduction of thyrotrophs hormone. 



Parathyroids. The parathyroid glands comprise four small bodies, two on 

 each side, attached to or imbedded in the dorsal surface of the thyroid. Function- 

 ally they are entirely independent of the latter. They secrete parathormone, which 

 regulates calcium metabolism of the body. Removal of these glands quickly 

 causes death. In excess parathormone leads to removal of calcium from the bones 

 and its addition to the blood and may result in the formation of calcium deposits 

 in the kidneys, ureters, or various body tissues. 



Adrenals. The adrenal (or suprarenal) glands rest atop the kidneys like two 

 miniature cocked hats. They are about 2 inches long and l{ to x i inch thick. 

 Each consists of two distinct parts, an outer cortex and an inner medulla. Embryo- 

 logically the cortex is derived from the same body layer as the kidney, but the 

 medulla comes from the same embryonic structures as the autonomic nervous 

 system and is largely composed of nervelike tissue. 



Cortisone (cortin) is the hormone or group of hormones produced by the adrenal 

 cortex. It seems to be the most versatile and perhaps the most essential of all the 

 hormones. Chemically it belongs to the steroid group, but it has not yet been fully 

 analyzed. There is reason to suppose that it is actually a hormone complex, in 

 view of the diverse actions it controls. Removal of the adrenals causes death in a 

 matter of weeks, with the symptoms long known in Addison's disease. There is 

 first a bronzing of the skin; this is followed by profound weakness and languor; 

 gastric acid disappears from the stomach, and glucose is not absorbed by the 

 intestine; the body temperature drops several degrees; the blood loses water and 

 salt through the kidneys and rapidly diminishes in volume; toxic nitrogenous and 

 potassium wastes are retained and reach high concentration in the blood. Finally 

 the glucose level of the blood falls to zero, as in insulin shock, and death results. 

 All these effects can be counteracted by injection of cortisone. 



The prime function of this hormone seems to be to act as a regulator of functional 

 balance in the body. To any disturbing factor it sets up a counter action which, 

 while it may not restore the original condition, results in a new working balance. 

 It is to this property that it owes its palliative effects in a great variety of diseases 

 and other such disturbances as shock, burns, and wounds. It does not cure the 



1 One milligram of thyroxin produces an increase in heat equivalent to the oxidation 

 of 267 grams of glucose, with liberation of 400 grams of carbon dioxide and 160 grams 

 of water. 



