Rev. S. Hanghton on Animal Mecliamcs. 



283 



Tendons. 



Scapular tendon of biceps 1'112 



Radial tendon of biceps 1*119 



Mean M155 



From these specific gravities it was easy to determine the cross 

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

 of either one or the other. In this manner the following Table was 

 constructed : — 



Cross sections of Muscles and Tendo7is in an Adult Human Male Subject, 

 and Ratios of the same. 



From the preceding Table, it appears that the ratio of the cross 

 section of the muscles to that of the tendons may range from 7 to 

 28, or be four times as great in one case as in another. We may also 

 see in general, that the tendons exposed to the greatest amount of 

 friction have the, smallest coefficients of cross section. Thus the 

 radial tendon of *the biceps has a coefficient of 28*2, while the sca- 

 pular tendon, which undergoes the friction of passing over the head 

 of the humerus, has a coefficient of 18-0. Again, the Ext. oss. met. 

 poll., whose tendon winds round the radius, and has the duty im- 

 posed upon it of binding down the tendons of the radial extensors 

 of the wrist, has the coefficient of 7-7, as compared with 26*2 and 

 18-4, the coefficients of the comparatively free tendons of these 

 extensors. 



As it might be objected that the relative cross sections of muscle 

 and tendon, in a human subject that died a natural death, might be 

 exceptional in character, from wasting during the last illness, I de- 

 termined to test the question by experiment, and accordingly selected 

 a fine Pyrenean Mastiff for the purpose, which I killed by strychnia, 

 and dissected immediately after death, with the following results, 

 which were obtained, as before, by noting the specific gravities of the 

 muscles and tendons, and by weighing a measured length of each : — 



