ITS SCOPE AND METHOD 71 



generated. But in the living muscle-fibre its chemical 

 action, its metabolism, furnishes energy by which the 

 potential can be re-established to its primitive value 

 namely, there is a return to the less stable condition 

 which we in the case of the muscle term its resting 

 condition. To us here the interest of such statements 

 as these is the broad one that, partially speculative 

 though they may be, they serve to illustrate the essen- 

 tially chemical and physical character of the considera- 

 tions upon which physiology is based, and the enormous 

 and still almost virgin wealth of opportunity which the 

 cell-theory reveals in the body's structure as a field for 

 the play of chemical and physical reactions of a certain 

 kind. 



The cell-theory impresses on us that the chemistry 

 of each organ, let alone of the body as a whole, must 

 be a chemistry resultant from ten myriad tiny foci, each 

 an individual seat of oxygenation, reduction, polymeri- 

 zation, hydrolysis, katalysis, and what not. And return- 

 ing to the warmth of the body, we see that in it the 

 student has to deal not with one seat of heat production, 

 but with a countless number of microscopic furnaces, 

 with conditions and rate of action very different in some 

 from that which they are in others. The matter is there- 

 fore complex to unravel. 



Yet certain points are clear. Since the body is warmer 

 than its surroundings, its heat drains from it. The greater 

 the difference in temperature between it and its surround- 

 ings the quicker will be the drain. That difference is 

 measurable by thermometry. Thermometry shows that 

 the temperature of the outer surface of the body differs 

 from part to part. That of the face may differ consider- 

 ably from the hand. But at a small depth below the 

 surface the temperature is practically alike throughout 



