228 



HITCHCOCK'S ANATOMY 



New-born infant 130 to 140 



During the 1st year 115 " 130 



" " 2d " 100 " 115 



From the 7th to the 14th year 80 " 90 



" 14th " 21st " 75 " 85 



" 21st " 60th " 70 " 75 



Old age 75 " 80 



402. Causes affecting the Pulsations. — Muscular exer- 

 tion has a considerable influence upon the rapidity of the con- 

 traction of the heart. So also has the position of the body, 

 whether sitting, lying, or standing. The time of day or 

 night likewise has an important influence, the highest number 

 of pulsations being found at noon, and the fewest at mid- 

 night. 



403. Use of the Corpuscles.— The function of the Red 

 Corpuscles seems to be to convey oxygen to the tissues, and 

 as this is the agent which is continually promoting the change 

 or waste of the system, these corpuscles seem to be the great 

 agents for disassimilating the tissues and the blood itself. The 

 colorless or white corpuscles seem to be the agents by which 

 the repair of the body is effected, since they are greatly aug- 

 mented in number when there is a large wound to be healed, 

 or when there is a great amount of internal or external in- 

 flammation. 



403a. Statistics. — In an ordinary life of a man the heart 

 beats at least 3,000,000,000 times, and propels through the 

 aorta one half a million tons of blood. 



HYGIENIC INFERENCES. 



404. But few Diseases of the Circulatory Organs. — - 

 1. Though the blood-vessels are so constantly in use, and so 

 easily excited by every muscular movement and mental emo- 

 tion, yet they are affected by only a few diseases, and many 



401. State the number of pulsations of the heart at different periods of life. 402. What 

 causes modify the number of the pulsations ? 403. What is the probable business of the 

 Bed Corpuscles? What of the White? 404. Are there many diseases of the Circulatory 

 organs ? 



