10 THE INTERNAL SECRETIONS 1920 



basic physiologic regulators, the internal secretions, are 

 in perfect adjustment in what might be called a phy- 

 sio-chemical equilibrium those organs will not func- 

 tion in harmony. Some or all of them either will run 

 too slow or too fast with a resultant state of ill health. 

 The most important of the endocrine glands may be 

 roughly classed physiologically, thus: 



(1) The Thyroid; metabolism, growth, antitoxic. 



(2) The Adrenals; blood-pressure, arterial tension, 



muscular tone. 



(3) The Pituitary; heart, unstriped muscles, renal 



secretion. 



(4) The Gonads; sexuality, reproduction. 



The secretions they manufacture are called "inter- 

 nal" because they go directly into the circulation with- 

 out first being conveyed into other glands or organs or 

 undergoing any change. Hence, they are internal with 

 reference to the blood current. 



Speaking in a general way, the adrenals and pitu- 

 itary control the action of the heart. Either a hyper- 

 or hypo-function of these glands will disturb the sta- 

 bility of its action. Either it will lose its normal power 

 of contraction, become enfeebled blood-pressure low, 

 circulation retarded, extremities cold, more or less 

 edema of the lungs and viscera hence, difficult res- 

 piration and imperfect digestion ; or else the heart will 

 contract with too much force the blood pressure is 

 high, skin flushed, high nervous tension, headache more 

 or less constant, apoplexy threatening. Such are the 

 chief symptoms of adrenal dysfunction. 



To the consideration of these two, let us add another, 

 the thyroid. This gland, taken in connection during 

 early life with the thymus, influences the growth and 

 development both physical and mental of the child. 

 During adult life it continues to influence metabolism ; 

 also, it has remarkable antitoxic action. Therefore, 

 the grave pathological effect of any disturbance of its 



