A POSTAL SYSTEM 229 



kind of machine — except in that kind which is made by 

 Nature. 



Long ago men discovered that the sex glands had a 

 powerful influence on the growth of the body. They 

 were well aware that the nature of both body and mind 

 became altered if the genital glands were removed in 

 youth. The whole build of body becomes more slender 

 in the castrated ; muscles are less robustly developed ; 

 the bones of the limbs grow longer, but are less power- 

 ful ; the beard fails to sprout ; the larynx undergoes no 

 transformation as adult years are reached ; the sexual 

 system retains a boyish development ; there is a marked 

 tendency for fat to gather on certain parts of the body ; 

 the mental outlook and the resolution for action are com- 

 pletely altered. In the eunuch we seem to be dealing 

 with a new species of mankind. All these facts were 

 known long ago, but it was not until we had grasped 

 the idea that the growth of the body is regulated by 

 hormones that we understood how castration brought 

 about such remarkable changes in the body. John 

 Hunter knew that the state of the genital glands regu- 

 lated the development and growth of the sexual system. 

 By transplanting the genital glands, and also parts of the 

 body which he knew formed part of the sexual outfit — 

 such as the spurs on the legs of fowls — he observed that 

 definite alterations could be effected by altering the 

 nature of the sexual glands. But it was not until we 

 came to know of growth-regulating substances that we 

 clearly perceived in the genital glands a double function. 

 They are not only seed treasuries, but also busy offices 

 from which missives are being constantly dispatched to 

 the adrenals, thyroid, pituitary, and other growth-control- 

 ling laboratories. Certain changes are effected through 

 the adrenal glands. In their cortex there is a laboratory 

 for the manufacture of hormones which stimulate the 

 appearance of sexual characters. Occasionally a child, 

 scarce off" its mother's lap, begins to assume, as a mon- 

 strous garb, the face, voice, and demeanour of sexual 

 maturity. Such a manifestation is always accompanied 



