GLANDS AS AN INTERLOCKING DIRECTORATE 101 



body beyond the control of the will (that is to say, the brain) 

 with two sets of filaments which have opposing functions. One 

 group of filaments in general increases or activates the function 

 of the organ to which it is distributed. The other group of 

 filaments, when tingling, inhibits or prohibits that function. 

 They are like the two buttons on the wall which regulate the 

 supply of electricity to incandescent bulbs, one switching on the 

 current, the other switching it off. It has been agreed to call the 

 stimulative or activating portion the autonomic or drive system. 

 To its antagonist has been left the older name of the sympathetic 

 or check system. It is because they do not both act upon these 

 two components of the vegetative nervous system, but only upon 

 one, that the thyroid and adrenal though in themselves comple- 

 mentary, come to exert opposite effects. For the internal secre- 

 tion ol the thyroid has a selective affinity for the autonomic or 

 activating system, while that of the adrenals has a selective 

 affinity for the sympathetic or inhibiting system. 



In the stomach, for instance, extracts of the adrenal glands 

 have been proved to intensify the function of the sympathetic or 

 check system in different degrees, so that there is a lessening of 

 the amount and acidity of the gastric fluid. On the other hand, 

 thyroid extracts will intensify the action of the autonomic or 

 drive system, so that the amount and acidity of the digestive 

 juice is increased. 



The stomach cell may, therefore, be regarded as a test-reagent 

 for the different internal secretions, as they affect the check and 

 drive systems. 



These constitute an automatic device for regulating the activi- 

 ties of every organ. Three factors enter into the mechanism. 

 One is the amount of the circulating internal secretions. Another 

 is the organic and functional integrity of the nerve filaments 

 comprising the check and drive systems. The third consists 

 of the number and vitality and limitations of the terminal re- 

 ceiving cells acted upon by the nerve filaments, which in their 

 turn have been acted upon by the internal secretions. Upon 

 every organ, including the mind, through the brain, a stimulus 

 from without or within will act according to its ability to influ- 

 ence one or others of these factors. 



Normally, the check and drive systems are properly balanced. 

 But under stress and strain the balance is upset. Indeed, the 

 Kinetic Drive may be defined as a mechanism contrived in the 

 course of evolution as the normal, healthy mode for meeting 



