1867.] 



Principles iti Anhnal Mechanics, 



23 



marcMan views it must have perfectly accommodated itself to the uses 

 to which it is applied. According, therefore, to either view, if the 

 tendon be too strong, it will become atroplded down to the proper limit; 

 Fig. 1. Fig. 2. 



Gracilis. Sartorius. 



and if too weak, it must either break, or be nourished up to the requi- 

 site degree of strength. It seemed to me desirable to prove this funda- 

 mental proposition in animal mechanics by direct observation ; and I 

 selected for this purpose the tendons in the leg of several of the large 

 running birds {Strutldonidce) ; and always with the same result, viz., 



