66 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
First, then, we think it now conceded by all that there is a natural 
law by which all organic 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? Following out embryogenic changes we must 
necessarily place nutrition of blood and its renovation 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, exercise, &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 
