30 



ANIMAL MECHANICS. 



In order to find the quantity of muscle that gives out the 

 preceding quantity of work, it would be necessary to know 

 the weights of the living muscles in each of the persons ob- 

 served; but, as this, except in rare cases, is impossible, we 

 must endeavour to obtain the result, indirectly, by observa- 

 tion of the muscles in the dead subject. With this object in 

 view, I carefully dissected the muscles in four dead bodies, 

 selecting those only that were well developed, and had not 

 experienced much wasting of muscular tissue during their 

 last illness. From these dissections, I obtained the following 

 results : — 



Table III. — Weights of Muscles. 





Supraspinatus. 



Portion of Deltoid 

 employed. 



Deltoid. 



A. Female, 



B. Male, 



C. Male, 



D. Male, 



i.oi oz. av. 

 1.76 „ 

 2.18 „ 



1-75 M 



1.82 oz. av. 

 2.98 „ 

 3-99 » 

 2-53 » 



7.10 oz. av. 

 10.16 „ 

 12.97 „ 

 10.25 „ 



Means, 1-675 oz. 



2-830 OZ. 



IO 12 oz. 



The only difficulty in these observations consists in estimat- 

 ing the portion of the deltoid actually employed in holding 

 the arm horizontal ; this was done by holding the arm in that 

 position while dissecting the deltoid, and estimating as well 

 as I could the fibres actually in action. It will be seen that 

 my estimate varies somewhat in the different cases, as fol- 

 lows : — 



In A, the portion of Deltoid was -3^-5 th of the whole. 

 ji B, ,, 

 >> P> >> " 



Mean, 



^th of the whole. 



