84 



ANIMAL MECHANICS 



make use of the right arm and hand of a well-developed sub- 

 ject (male) brought into the dissecting room of that College, 

 in March, 1868. 



I first ascertained the specific gravities of muscles and 

 tendons, with the following results : — 

 Muscles. 



Sp. Gr. 



Biceps humeri, 1.050 



i-o54 



Brachueus, . 1.05^ 



Mean, . . . 10523 



Tendons. 



Scapular tendon of biceps, . . 1 . t 1 2 



Radial tendon of biceps, . . 1 • 1 1 9 



Mean, . . . 1.1155 



From these data it was easy to determine the cross sec- 

 tion of either muscles or tendons, by weighing a known length 

 of either one or other. The following Table was thus readily 

 constructed : — 



Table XII. — Cross Sections of Muscles in an Adult Human 

 Male Subject. 



Muscle. 



Weight of 

 Muscle. 



Length of 

 Muscle used. 



Weight of 

 Muscle used. 



Cross Section. 



1. 



Biceps humeri, . . 



3.48 oz. av. 



3 inches. 



713.8 grs. 



0.89$ sq. in. 



2. 



Palmaris longus, . 



0.22 „ 





39-4 t, 



0.148 ,, 



3- 



Ext. carp. rad. longr., 



1.26 „ 



2 ,, 



310.6 ,, 



0.584 „ 



4- 



Ext. carp. rad. brevr., 



0.81. „ 



2 ,, 



215-3 » 



0.405 



5- 



Biceps humeri (long- 









°-379 



head), .... 



}.. .. 



5 n 



503-9 » 



6. 



Fl. pollicis long., . . 



o.44 » 



1 ,, 



60.6 „ 



0.228 „ 



7- 



Fl. carp, rad., . . . 



o.53 „ 





124.6 „ 



0.234 „ 



8 



Ext. carp, uln., . . 



0.58 „ 



1 ,, 



56.5 „ 



0.212 



9- 



Fl. digit, subl., . . 



2.2 1 , 



2 ,, 



328.4 „ 



0.618 „ 



10. 



Fl. dig. prof., . . . 



2-74 » 



2 ,, 



408.2 „ 



0.768 „ 



11. 



Ext. oss. met. poll., . 



0-52 „ 



2 ,, 



118.7 „ 



0.223 „ 



12. 



F. carp, uln., . . . 



0.83 .» 



2 ,, 



97-o „ 



0.182 „ 



i3- 



Bracbialis anticus, . 



3- '3 „ 



3 „ 



736.o „ 



0.923 „ 



