ANIMAL MECHANICS. 



71 



I believe that the difference between this result and that 

 found by me, viz. 102.55 lbs. per inch, is a real difference 

 arising from the fact that these observers used the cross sec- 

 tions of muscles as they occur in ordinary dead bodies, 

 whereas I took care to use the cross sections of muscles in a 

 strong man, who had died quickly by cholera, and in whom I 

 supposed the muscles would be found in a state more nearly 

 approaching that in which they occur in the living body. 



If we compare the cross sections of the biceps and bra- 

 chiceus found in ordinary dead bodies by Bonders and Mans- 

 felt (p. 65) with those employed by me (p. 63), we find — 



Cross Sections of Muscles of Arm. 



Donders and Mansfelt. Haughton. 

 Biceps humeri, . . 1.522 sq. in. 1.914 sq. in. 

 Brachiceus, . . . 0.952 ,, 1.276 ,, 



2.474 3.190 



If we wish to ascertain the coefficient of muscular con- 

 traction per square inch of cross section of living muscle, we 

 must alter the coefficient of force per square inch of cross 

 section of dead and wasted muscle in the proportion of 2474 to 

 3190. This will give us, as the coefficient of living muscle, 

 from the experiments of Henke and Koster, 



Coefficient of contraction 1 123.04 x 2474 



pi. • -. Y = 95.42 ibs. per 



of living muscle, J 3190 sq. inch 



This result comes very near that found by me as the co- 

 efficient of the flexors of the forearm, viz. 94.7 lbs. 



I have proved (pp. 42, 43) that the same muscles, when 

 moderately worked, give out equal quantities of work before 

 becoming fatigued ; but this statement requires to be modi- 

 fied, when applied to the amount of work performed suddenly 



