1 10 PHYSIOLOGY. 



How the Body differs from a Locomotive. By a 



closer examination he would find out some of the differ- 

 ences that we have noticed : 



1. That the body does not get hot enough to burn; i.e. 

 the oxidation is relatively slow, and is not combustion. 



2. That the oxidation of the body never produces light. 

 . 3. That the oxidation here is always in the presence of 



moisture. 



The Amount of Carbon Dioxid given off. When the 

 breath is held for some time, the carbon dioxid in the ex- 

 pired air may reach 7 or 8 per cent. During violent 

 exercise the amount of carbon dioxid given off may be 

 from two to two and a half times as much as when we are 

 at rest. The amount of carbon dioxid given off is in- 

 creased in cold weather, and by taking food, and decreased 

 from one fifth to one fourth during sleep. Oxygen is 

 carried chiefly in the corpuscles, but the carbon dioxid is 

 carried in both plasma and corpuscles. 



Storage of Oxygen in the Tissues. The activity of the tissues 

 from their oxidation does not necessarily mean that the oxidation is 

 direct ; that is, that the oxygen is used as soon as it is brought to the 

 tissue. For instance, in the muscles it is believed that the oxygen is 

 stored in some form, probably in combination, so that it can be used 

 when needed, perhaps much more rapidly than could be supplied by the 

 respiration at the time. If we study the chemistry of explosion, we 

 learn that it is a very rapid combustion. In the explosives are ma- 

 terials that unite instantaneously, instead of slowly burning, as in the 

 case of ordinary combustibles. / 



The Action of Muscles like an Explosion. Now, many physiolo- 

 gists hold that a sort of explosive compound is formed in the muscles, 

 and that when the muscle acts it does so as the result of the explosion, 

 so to speak, of this material. And, to carry out the figure, the nerve is 

 compared to the match that ignites the explosive. A little heat is 

 enough to cause the most violent explosion. So the force that passes 



