HORSE-BACK RIDING. 21 



then, is only submitted to agitations and concussions 

 more or less great and frequent, which penetrate it, 

 so to speak, and act upon all its parts. These mo- 

 tions stimulate the tissues, increase the organic ac- 

 tivity, and render the execution of nutritive functions 

 more easy. They do not excite, as is the case in 

 great active exercises, disturbance in the digestion, 

 circulation, or respiration ; they do not increase ani- 

 mal heat and perspiration ; they do not cause either 

 loss or fatigue ; they are therefore suited to conva- 

 lescents, and to individuals of weak constitution. 



3. Effects of mixed exercises. — Mixed exercises, and 

 specially horse-back riding, unite in themselves the ad- 

 vantages of active movements, and those of commu- 

 nicated or passive movements. They have on the 

 muscles and on the viscera an action more powerful 

 than the last, and that action has not, like the great 

 muscular contractions, the inconvenience of bringing 

 on great fatigue and an abundant loss of nutritive 

 material ; thus the mixed exercises are almost suit- 

 able to all ages, to most temperaments, and, above 

 all, to all individuals who by constitution are not 

 strong enough to take great active exercises, yet have, 

 however, need of more movement than simple gesta- 

 tion. 



