THE SYSTEM 63 



certain physical effects, some of them effects not 

 to be suspected by the uninformed reader. 

 There seems to be very good evidence that the 

 growth of antlers in deer depends upon an internal 

 secretion from the sex-gland and from the inter- 

 stitial tissue of that gland ; for it is apparently 

 upon the secretions of this portion of the gland 

 that the secondary sexual characters depend, 

 and not merely these, but also the normal sexual 

 instincts. And this takes us a stage further. 

 The extreme claim is that all instincts, in fact 

 all thoughts and operations, are in the last analysis 

 chemical or chemico-physical. Let us examine 

 this claim for a moment. The adrenals are two 

 inconspicuous ductless bodies situated immedi- 

 ately above the kidneys. Not many years ago, 

 when the present writer was a medical student, 

 all that was known about these organs was that 

 when stricken with a certain disease, known as 

 Addison's disease from the name of its first 

 describer, the unfortunate possessor of the dis- 

 eased glands became of a more or less rich 

 chocolate colour. To-day we know that the 

 internal secretion of these organs is a very power- 

 ful styptic, and there is good reason to believe that 

 a copious discharge accompanies an unusual 

 exhibition of rage. When we are told things of 

 this kind we must first of all remember that the 

 adrenalin does not cause the rage, though it may 

 produce its concomitant phenomena. If a man 

 flies into a violent passion because someone has 

 trodden upon his corns, and there is a copious 

 flow of adrenalin from the glands, it is not that 



