360 ANIMAL MECHANICS. 



The results obtained from the calculation of the equivalent 

 fibre OO', furnish us with more than a proof of the Postulate; 

 they give us, as I believe, an inner insight into the reason for 

 the invention and use of skew muscles. In order to illustrate 

 my meaning, I shall place, in the form of a Table, the dis- 

 tances of the points of insertion on the femur, of the longest 

 and shortest fibres of the muscle, together with the distances 

 of the point of insertion of the (imagined) equivalent 

 fibre OO'. 



Position of Equivalent Fibre. 





Distance from 

 Socket to upper 

 end of inser- 

 tion. 



Distance from 

 Socket to lower 

 end of inser- 

 tion. 



Distance from 

 Socket to 

 insertion 

 of 00'. 



Adductor seeundus (/3). 









1. Llama, 



2. " Master Magrath," . 



3. Woman, .... 



4. Leopard, .... 



2.52 in. 

 3- 10 » 

 3-32 » 

 '•47 » 



8.53 in. 

 6.16 „ 

 13. 10 ,, 

 6. 70 „ 



3. 14 in. 

 2.28 „ 

 3- 6 4 „ 

 2 -3 2 » 



Adductor seeundus (a). 









5. Leopard, .... 



i-47 » 



6. 70 ,, 



2.58 „ , 



This Table shows clearly the tendency of the skew form 

 of muscle to bring the resultant line of force higher up on the 

 femur, and nearer to the hip joint; but it may be still better 

 seen from the next Table, which gives the actual transfer on 

 the femur from the point of bisection of the line of insertion 

 along the limea aspera, 



