Proceedings of the Ohio State Academy of Science 457 



gan. In so doing the pressure is released in the organ and 

 more blood comes to it on account of the elacticity of the 

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

 cular activity is responsible for a large part of the reduction 

 of pressure in the organs. The muscles of the arm for ex- 

 ample upon contracting increase in diameter which causes 

 ])ressure to be brought to bear u])()n the veins. 'Inhere l)eing 

 valves in the smaller veins opening toward the heart the l^lood 

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

 heart. A casual observation of the muscular activities of the 

 body wall show their importance and their general distribu- 

 tion. The digestive processes show it from beginning to end. 

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

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

 muscular action. The heart beat in pumping the blood into 

 the aorta to keep up the pressure in the arterial system is 

 muscular activity. The processes of respiration all depend 

 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- 

 tivity the greater the oxidation producing a greater amount of 

 waste matter in the form of C()..\ C()2 is the stimulant for 

 the respiratory center wdiich has control of the respirator\- 

 operations. Therefore the greater the muscular activitv the 

 greater the speed of the respiratory operation and the better 

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

 the lungs, more oxygen absorbed into the Idood. a greater 

 amount of the life giviitg element wdth a suljseciuent better 

 general health. Nature's method of bringing this about is 

 shi^-ering. If the temperature of tlie ]:)od\- becomes low for 

 any cause theniuscles are set int(^ sudden contraction, wdiich 

 starts the circulation with the result as stated above. The 

 heart beat depends ui)(^n the amount of heat in the blood and 

 the lack of pressure in the aorta. Oxidation is producing heat 

 while the C02 is beino- made. The rate of heart beat is there- 

 fore increased in speed and the heart muscles themsehes in- 



