Procicdinys of the Ohio State Academy of Science 4.")^ 



ijan. In so doini^ the pressure is released in the origan and 

 more blood conies to it on account of tiie elacticitv of tin- 

 arteries and the pressure in the general arterial system. Mus- 

 cular activity is responsible for a large i<art of the reductiini 

 of ])ressure in the organs. Idie muscles of the arm for e.\- 

 amjjle upon contracting increase in diameter which causes 

 p;essure to be brought to bear u;)on tlu ve'ns. There being 

 valves in the smaller veins opening toward tlie heart the blood 

 can go in but one direction, i. c, out of th.e organ toward the 

 heart. A casual observation of the muscular activities of the 

 body will show their importance and tlieir general distribu- 

 tion. The digestive prt:)cesses show it from beginning to end. 

 The mastication of the food, the action oi the stomach, and 

 the action of the intestine in moving the food along, all are 

 muscular action, 'idle heart beat in pumping the blood into 

 the aorta to keep u}) the pressure in the arterial system i> 

 muscular activity. The processes of respiration all (le])eud 

 upon muscular activity. 



The rate of heart beat and the rate of respiration depends 

 upon the general muscular activity, in that the greater the ac- 

 ti\dty the greater the oxidation producing a greater amount of 

 waste matter in the form of C02. C( '*> is tlic stimidant for 

 the respiratory center which has control ot the rcspirator\' 

 o|)erations. Therefore the greater the muscular acti\it}' the 

 greater the speed of the respirator}- operation and the better 

 the ventilation of the lungs. This means more air taken into 

 tlie lungs, more oxvgen al)Sorbed into the l)lood, a greater 

 amount of the life gi\ing element with a subsecpient better 

 general health. .\ature"s method of l)ringing this about is 

 shi\-ering. If the tem])erature of the body l)ecomes low for 

 an\- cause the muscles are set into sudden contraction, which 

 starts the circulation with tlie result as stated al)o\e. The 

 lie'U't beat dei)ends u])on the amount of heat in tlu' blood and 

 the lack of pressure in the aorta. ( )xidation i> ])ro(lucing heat 

 while the ("()'-' is being made. The rate of lieart beat is there- 

 fore increased in sj)eed and the lieart niuscle> theniseKes in- 



