Chemico-Functional Integration 131 



the paths which must be followed in order that more exact 

 knowledge may be gained." 



Experimental Evidence of Connection Between the Adrenal 

 Glands and the Nervous System 



Some of the most important information we have in this 

 field is furnished by Cannon and his collaborators concern- 

 ing the secretion of the adrenals and its relation to the 

 autonomic and central nervous systems. It had been proved 

 before Cannon began his investigations that adrenin injected 

 into the blood has exactly the same effect on certain parts 

 of the organism as does the sympathetic autonomic nerves 

 with which the same parts are supplied, and that the effect 

 of the secretion is direct and not through the nerves. In 

 other words, it had been proved that the organism has two 

 methods by which the same activity of certain of its parts 

 can be induced, one nervous, the other chemical. Thus the 

 dilation of the pupils, the erection of hairs, the inhibition 

 of activities of the alimentary canal, and the liberation of 

 sugar from the liver can be induced either through sym- 

 pathetic autonomic centers or by the secretion of the adrenal 

 bodies. This in itself was important evidence of interrela- 

 tion between the nervous system and internal secretory sys- 

 tem. But the experimental researches prosecuted in Can- 

 non's laboratory have proved that a connection exists be- 

 tween the autonomic-adrenal phenomena and the cerebro- 

 spinal system through the sensory nerves, and with the 

 psychic life of the animal ; and have shown the probable sig- 

 nificance of the entire scheme for the life of the organism as 

 a whole. 



To be a little more specific, they have proved: 

 (1) That strong excitation of sensory nerves stimulates 

 reflexly the adrenal glands and causes them to pour an 

 increased amount of adrenin into the blood. 



