312 ELEMENTS OF PHYSIOLOGY 



reflexly to the vasomotor nerves and to the sympathetic 

 fibers of the intestine ; these are " toned up " and restore 

 activity to the involuntary muscles. 



571. Connection of Body with Brain and Mind. The 

 pulse rate is affected by every emotion. Shame causes 

 the blood vessels of the face to dilate. Painful emotions 

 excite the activity of the lachrymal or tear glands. Joy 

 increases ease of movement. If an excited or angry man 

 who is walking to and fro sits down, his excitement de- 

 creases. A starving man and one suffering from fever 

 have hallucinations. The Romans had the proverb " a 

 sound mind in a sound body." The care of the body for 

 the mental effect as well as for the sake of the body itself, 

 is only gradually regaining the high place it held among 

 the Greeks and the Romans, a place which it lost dur- 

 ing the Dark Ages. " Hysteria and nervous exhaustion 

 are the fruits not of overwork, but of lack of varied and 

 interesting employment. The absurd opinion that hard 

 work is menial and low, leads to most pernicious conse- 

 quences. The girl who, turning from brain work to 

 manual labor, can cook, scrub, wash, and garden, invites 

 the bloom of health to her cheeks ; while the fine do- 

 nothing lady loses her good looks, suffers from the blues, 

 and is a nuisance to her friends and a misery to herself." 



572. Two Kinds of Tired Feeling. if a person works 

 hard mentally or physically, the nutrition stored in his 

 cells is consumed by the oxygen. Carbon dioxid, urea, 

 and other products of oxidation, accumulate ; this decreases 

 the production of heat, smothers the vital fire, as it were, 

 and stops the setting free of energy. The muscles may 

 ache with fatigue or the brain grow drowsy; this is the 

 natural and healthful kind of tired feeling. It leads to rest 

 and recuperation. During the interval of rest, even if no 

 new food is absorbed from the canal, digested food, already 

 in the blood, and lymph are built up into living tissue again, 



