176 Qattle Problems. 



conditions. Motion in the muscles causes wearing change ; 

 wear gives occasion for renewal, causing a demand for nu- 

 tritive blood supply, in proportion to motion and waste. 



Motion, or exercise, increases nutritive blood by in- 

 creasing breathing, which completes the nutritive quality 

 of the blood, by adding oxygen to it. Without oxygen, 

 blood does not circulate. So exercise increases blood 

 supply co-equally with, and in advance of, the demand to 

 nourish or repair AA'orn muscular tissue in all muscular 

 organs and parts of the body. Thus, while motion is 

 necessary to maintain the elasticity and size of the 

 muscles, or muscular parts, it also increases the blood sup- 

 ply that is necessary in the fibres and strands of fibres 

 forming the muscles, and in all muscular structure, in ad- 

 vance, and in proportion both to motion and to the wear 

 arising from it. 



Nutrition, practically considered, consists in the or- 

 ganizing of vitalized blood. This flows into the tissues 

 and muscular fibres in proportion to their motion. It is 

 this supply of blood that keeps the muscles and their fibre 

 alive, by its organization. But organization, or renewal, 

 in the muscles, is reduced or ceases in such degrees as mo- 

 tion or use, and blood supply, are reduced and discontin- 

 ued ; and muscles rapidly waste away, fibre after fibre dis- 

 appearing, from the inaction resulting from rapid and ex- 

 treme reduction of exercise. 



Muscles may recover their size again, if exercise — which 

 develops fibrin in the blood, be increased sufficiently 

 and early enough, to insure the requisite blood supply 

 to the muscles corresponding with reduction in motion and 

 wear; and the blood flow in the fibre vessels ceases entirely 

 soon after complete inaction and disuse in the muscles 

 and fibres takes place. When the action of the fibres 

 ceases, their circulation also ceases ; organization ceasing 

 in the fibres from t\\z stoppage of their red-blood [circulation. 



