66 PROCEEDINGS OF THE CANADIAN INSTITUTE. 



First, then, we think it now conceded by all that there is a natural 

 law by which all oi'ganic life unconsciously seeks rest, in order as it 

 were to store up energy for the renewal of active functions. As far 

 as we know all animals follow this law : we know as well that plants 

 do. How this takes place in plants we know in the fact that the 

 actinic rays of the sun, aiding the decomposition of carbonic acid by 

 the plant and the assimilation by it of carbon, thereby become the 

 exact idex of this functional activity. Nothing then seems more 

 certain than that man's physical, and likewise intellectual, nature 

 seeks in sleep that rest which enables the various organs to revitalize 

 themselves by both lessening the physical waste, and the storing up 

 of new energy. But this process, inherent in the natural constitution 

 of man, must of course be carried on by means of natural processes. 

 What are these 1 Following out embryogenic changes we must 

 necessarily place nutrition of blood and its i-enovation first. But 

 since nerve force is that which evolutionary progress has carried to 

 its highest point of development in man, we feel that in adult man 

 it should almost be placed first, so potent a regulator has it become 

 of the processes of nutrition. We may say then that nerve force 

 exists through all the degrees from extreme nerve tension to that of 

 complete nerve relaxation, the various degrees depending upon the 

 ability to assimilate nourishment, derived from the blood and external 

 warmth, light, exei-cise, &c. Now in trying to explain physical 

 phenomena and the part played by nerve matter in them, it is neces- 

 sary to proceed with the greatest caution, since we frequently find 

 popular expressions and scientific expressions diameterically opposed 

 to one another. Thus the popular expression for nerve anaemia or 

 nerve debility is nervousness, which in reality ought to mean the 

 very opposite, viz., nerve force; and so a whole series of misused 

 expressions originating in wrong pathological ideas might be given. 

 Starting then somewhere in the complex circle of cause and effect 

 let us suppose that nerve force is given. Now it seems generally 

 accepted that the ganglionic system of nerves, which especially sub- 

 serves the functions of organic life, is that too which, by giving nerve 

 supply to the muscular tissue of the blood vessels, regulates the blood 

 supply of a part, either by contraction of the walls lessening the 

 blood supply, or relaxation causing a temporary hyperaemia. (It 

 should be noticed here that the hyperaemia attendant upon inflam- 

 mation seems to some extent at least dependent upon some morbid 



