SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 259 



with nutritious material and the ever-active scavenger, 

 oxygen. 



670. Inf. Since time is required for the Blood to course through 

 the relaxed MUSCLE, IT SHOULD NOT BE CONTRACTED AGAIN INSTANTLY ; if 

 it is, it cannot renew itself as rapidly as it decomposes, and is soon ex- 

 hausted. 



571. Illus. A horse driven rapidly with a light load, day after day, 

 falls off; while a horse driven slowly, drawing heavy loads, improves. 

 Stage-horses improve during bad going, and fall off when the roads are 

 good. 



672. Inf. Light work rapidly performed is more wearisome than 

 laborious work. 



673. Remark. Such work as sewing is very wearing if long con- 

 tinued, from the frequent contraction of muscles which, though small 

 and few, are not allowed sufficient time for relaxation ; from the contin- 

 ued contraction of some ; from the entire inactivity of others ; from be- 

 ing done in close, uninviting rooms, and under few of the stimulating 

 emotions, hope, good pay, etc. Relief can and should be given in most 

 of these respects. (See Ap. L.) 



574. SINCE THE MUSCLES REQUIRE A LARGE FLOW 

 OF BLOOD, it follows that tight clothing of the chest, 

 hands, or feet, will not only prevent free muscular con- 

 traction in those parts, producing stiff and awkward 

 movements, but also injure the muscles by cutting off 

 their supply of Blood. 



575. Particularly WHEN PERSONS (or animals) ARE 

 GROWING, the muscles ought not to be constrained, and 

 should not be over-tasked, but should be allowed con- 

 siderable repose, and a free circulation promoted. 



576. WHEN A FREE CIRCULATION is PERMITTED, and 

 alternate contraction and relaxation of the muscles, 

 with proper periods of repose, are allowed or caused, 

 they will increase in size and vigor wonderfully. 



677. Illus. A BLACKSMITH'S ARMS become large, hard, and strong, 

 from the effects of exercising them, but the right is no healthier than 

 the left one. 



5TO. What said of? 5T1. Illustrate. 5T2. Illustrate. 573. What said of sewing? 

 674. What follows? 5T5. What said ? 576. What results ? 577. What said of-? 



