TABLE OF PHYSICAL CONSTANTS. 167 



Function of red corpuscles ; to carry oxygen from the lungs to the tissues. 

 Frequency of the heart's pulsations per minute ; 72, on the average. 

 Velocity of the blood movement in the arteries; about 16 inches per 



second. 

 Length of time required for the blood to make an entire circuit of the 



vascular system ; about 20 seconds. 

 Amount of air passing in and out of the lungs at each respiratory act ; 



from 20 to 30 cubic inches. 

 Amount of air that can be taken into the lungs on a forced inspiration ; 



no cubic inches. 

 Amount of reserve air in the lungs after an ordinary expiration ; 100 



cubic inches. 

 Amount of residual air always remaining in the lungs ; about 100 cubic 



inches. 



Vital capacity of the lungs ; 230 cubic inches. 

 Entire volume of air passing in and out of the lungs in 24 hours ; about 



400 cubic feet. 



Composition of the air; nitrogen, 79.19, oxygen, 20.81, per 100 parts. 

 Amount of oxygen absorbed in 24 hours; 1 8 cubic feet. 

 Amount of carbonic acid exhaled in 24 hours ; 14 cubic feet. 

 Temperature of the human body at the surface ; 98 1 6 ^ F. 

 Amount of urine excreted daily ; from 40 to 50 ounces. 

 Amount of urea excreted daily; 512 grains. 

 Specific gravity of urine ; from i.oio to 1.0*5. 

 Number of spinal nerves; 31 pairs. '' r 

 Number of roots of origin; two; ist, anterior, motor; 2d, posterior, 



sensory. 



Rate of transmission of nerve force ; about 100 feet per second. 

 Number of cranial nerves ; 12 pairs. 



f i. Olfactory, or ist pair. 

 2. Optic, or 2d pair. 



Nerves of special sense : 3- Auditory, or 8th pair. 



I 4. Chorda tympani for anterior % of tongue. 



Branches of glosso-pharyngeal, or 8th pair, 



for posterior y of tongue. 

 Motor nerves to eyeball and accessory structures ; motor oculi, or 3d 



pair j pathetic, or 4th pair ; abducens, or 6th pair. 

 Motor nerves to facial muscles ; portio dura, facial, or 7th pair. 

 Motor nerve to tongue; hypoglossal or I2th pair. 

 Motor nerve to laryngeal muscles ; spinal accessory or nth pair. 

 Sensory nerve of the face ; trifacial or 5th pair. 



