life: its nature, origin, and maintenance SCHAFER. 519 



or cured by the administration of its juice. On the other hand, en- 

 largement of the thyroid, accompanied by increase of its secretion, 

 produced symptoms of nervous excitation, and similar symptoms 

 are caused by excessive administration of the glandular substance by 

 the mouth. From these obsei'vations it is inferred that the juice con- 

 tains hormones which help to regulate the nutrition of the body and 

 serve to stimulate the nervous system, for the higher functions of 

 which they appear to be essential. To quote M. Gley, to whose re- 

 searches we owe much of our knowledge regarding the functions of 

 this organ, "La genese et rexercice des plus hautes facultes de 

 I'homme sont conditionnes par Taction purement chimique d'un pro- 

 duit de secretion. Que Ics psychologues meditent ces faits." 



The case of the parathyroid glandules is still more remarkable. 

 These organs were discovered by Sandstrom in 1880. They are four 

 minute bodies, each no larger than a pin's head, embedded in the 

 thyroid. Small as they are, their internal secretion possesses hor- 

 mones which exert a powerful influence upon the nervous system. 

 If they are completely removed, a complex of symptoms, technically 

 known as "tetany," is liable to occur, which is always serious and may 

 be fatal. Like the hormones of the thyroid itself, therefore, those of 

 the parathyroids produce effects upon the nervous system, to which 

 they are carried by the blood, although the effects are of a different 

 kind. 



PITUITARY GLAND. 



Another internally secreting gland which has evoked considerable 

 interest during the last few years is the pituitary body. This is 

 a small structure no larger than a cob nut attached to the base of 

 the brain. It is mainly composed of glandular cells. Its removal 

 lias been found (by most observers) to be fatal — often wdthin two or 

 three days. Its hypertrophy, when occurring during the general 

 grow^th of the body, is attended by an undue development of the 

 skeleton, so that the stature tends to assume gigantic proportions. 

 "When the hypertrophy occurs after growth is completed, the extremi- 

 ties, viz, the hands and feet and the bones of the face, arc mainly 

 affected; hence the condition has been termed "acromegaly" (en- 

 largement of extremities). The association of this condition with 

 affections of the pituitaiy was pointed out in 1885 by a distinguished 

 French physician, Dr. Pierre Marie. Both ''giants" and "acromeg- 

 alists" are almost invariably foimd to have an enlarged pituitary. 

 The enlargement is generally confmed to one part — the anterior 

 lobe^-and we conclude that this ])i-oduces hormones which stimulate 

 the growth of the body generally and of the skeleton in particular. 

 The remainder of the pituitary is different in structure from the an- 

 terior lobe and has a difi'erent function. From it hormones can be 

 extracted which, like those of the suprarenal capsule, although not 



