118 PHYSIOLOGY 



not supplied fast enough to oxidize the resulting 

 products. 



If too much exercise is taken habitually as often hap- 

 pens in the case of athletes, the effects may be disastrous. 

 When a muscle is properly exercised it increases in 

 size, if it is well nourished and well aerated it becomes 

 stronger and better able to work. This is true of the 

 heart as of every other muscle. 



The blood that passes through the heart at every 

 beat does not come intimately enough in contact with 

 the tissue of the heart to furnish the necessary nour- 

 ishment. This is brought by the coronary artery which 

 permeates its tissue. If too great demand is made on 

 the heart, the heart muscle becomes so thickened that 

 the coronary artery can not supply sufficient nourish- 

 ment, the muscle then degenerates and loses the power 

 to contract. 



The development of the athlete is not always towards 

 perfection. Where one set of muscles is used to the 

 exclusion of another set, the first becomes over-developed 

 at the expense of the latter. The result is the very dis- 

 agreeable condition that is called muscle-bound. 



Effect of Alcohol on the Nervous System. — Indul- 

 gence in alcoholic drinks has a decidedly deleterious 

 effect on the nervous system. 



Alcohol apparently stimulates the body and mind to 

 greater activity and it is taken frequently for its ex- 

 hilarating effect. In reality instead of stimulating the 

 brain to work more clearly it acts like a narcotic and 

 inhibits the activity of the restraining influences of 

 the will and of habit. This inhibition results at first 



