ANIMAL MECHANICS. 



375 



Abduction Muscles of Lion's Hip — Difference between Theory 

 and Observation, taking into account the relative importance 

 of each muscle. 



Muscle. 



Weight. 



Weight 

 E X 





Agitator caudae, .... 



6. 50 oz. av. 



'•395° 



2. 



Glutgeus primus, .... 



3-5" » 



1 . 4000 



3- 



Tensor vaginae femoris, . 



6 -5° »i 



1.6250 



4- 



Gluteeus seeundus (a), . 



2.50 „ 



0. 4000 



5- 



Glutaeus secimdus . 



14-50 „ 



3.0450 



6. 



Glutaeus tertius 



2-5° M 



0. 4500 



7- 



Glutasus quartus, 



o.53 » 



0. 1007 



8. 



Obturator internus, . 



4.00 „ 



0. 4000 





Total, . . 



40.53 oz. av. 



8.8157 



Dividing this last sum by the total weight of the muscles, we 

 find the mean error to be 0.217 of an inch, which agrees with 

 the former result. This agreement shows that, in the plan of 

 the Hip joint, the perfect action of each muscle, small and 

 great, is equally provided for ; just as in a well-ordered 

 republic, the happiness of the humblest citizen is of as much 

 importance to the State as the happiness of the citizen of 

 highest rank. 



Before leaving the muscles used in abduction, it may be 

 useful to record the actual directions of the axes round which 

 they cause the femur to rotate. 



We may take the longest axis of the pelvis joining the 

 tuber ischii with the anterior inferior spine of the ilium, as 

 our reference line, measuring the angles made with this line 

 towards the ischium, positive when above this line, and 

 negative w T hen below it. 



On laying down the several axes, I found the following : — 



