THE MUSCLES 41 



lar hours and during a regular period, the activity and the time 

 varying with the strength of the individual, and carefully 

 measured by it. (Head Note 3.) 



18. Different Modes of Exercise. There are very few who 

 have not the power to walk. There is required for it no 

 expensive apparatus, nor does it demand a period of prelimi- 

 nary training. Walking may be called the universal exercise. 

 With certain foreign nations, the English especially, it is a 

 very popular exercise, and is practised habitually by almost 

 every class of society ; by the wealthy who have carriages, as 

 well as by those who have none ; by women as well as by men. 



19, Running, leaping, and certain other more rapid and 

 violent movements are the forms of exercise that are most 

 enjoyed in childhood. For the child, they are not too severe, 

 but they may be so prolonged as to become injurious. Instances 

 have been recorded where sudden death has resulted after 

 violent playing, from overtaxing the heart: for example, we 

 have the case of a young girl who, while skipping the rope, 



3. The Ill-effects of Over-exertion. "It should be recollected that 

 the action of the muscles has limits, as well as that of every other organ 

 of the body. The muscles and the heart may be taxed too severely, and 

 permanent derangements may be produced by overtaxing the human 

 body. The ancient gymnasts among the Greeks are said to have become 

 prematurely old, and the clowns (or acrobats) and athletes of our own 

 days suffer from the severe strain put upon their muscular systems." The 

 effects of boat-racing in England have been thus described by Dr. Skey, 

 an eminent surgeon: "The men look utterly exhausted. Their white 

 and sunken features and pallid lips show serious congestion of the heart 

 and lungs, and the air of weakness and lassitude makes it a marvel how 

 such great exertion should have been so nobly undergone. We have 

 repeatedly seen the after ill-effects spitting of blood, congested lungs, 

 and weakness of the heart from over-distension." "Persons should 

 neither walk, run, leap, or play at any game, to the extent of producing 

 permanent or painful exhaustion. All exercise should be attended with 

 pleasurable feelings ; and when pain is produced by proper exercise, those 

 who suffer should rather seek medical advice than persevere in exercise." 

 Lankester's Manual of Health. 



18. What may walking be called ? What further is said of walking ? 



19. What is said of running, and other like movements ? What, as related to childhood ? 

 What instances are alluded to ? Example ? 



