72 



ANATOMY OF VERTEBRATES. 



37 



The Bimana are as expressly adapted to station and movement 



on the ground as are the Quadru- 

 inana to climbing in the forest. There 

 is no known connecting link between 

 the lowest variety of Man and the 

 highest species of Ape. No animal 

 is served by arms, at once so large 

 and variously flexible and applica- 

 ble as Man ; in none are the termi- 

 nal divisions of the limb so distinct 

 in their power and adaptability. 1 

 The mechanism of the vertebral 

 column and limbs which makes 

 Man a f plantigrade biped,' and the 

 only one in the Animal Kingdom, 

 is as perfect in the Mincopie, 2 

 Australian, or Boschisman, as in 

 the most advanced member of the 

 white race. The locomotive frame 

 of any variety would equally serve 

 as the subject of such elaborate 

 analyses of the mechanical condi- 

 tions of ( standing,' ' walking,' ' run- 

 ning,' ( leaping,' &c. as have been 

 given by Borelli, 3 Barthez, 4 Rou- 

 lin, 5 Gerdy, 6 and W. & E. Weber, 7 

 to whose works, and especially the 

 latter, the reader is referred for 

 this interesting branch of Animal 

 Mechanics. 



LX1V. 

 4 XIV. 



- XXXVII". 

 XV. 6 XVI". 



3 cxxxr 



7 XII". 



Figure 37 exemplifies a Man stooping with a load, and sustained in that position 

 by the glutei, f, the quadriceps feraoris, y, and the gastrocnemii, /. If the weight r 

 be 120 Ibs., that of the bearer 150 Ibs., and if the line r s be the direction of the force 

 of gravity cutting the femur and tibia in c and x, the centre of gravity of the Man being 

 at b, and the common centre of gravity of the Man and his load at a, then the weight 

 of the Man from the head to b will be = 'I Ibs. = 75 Ibs., and that of the section b 

 to c, by supposition, = 47 ; therefore the weight of the arc a b c = 75 + 47 = 122, 

 also by supposition the section c v x = 20, and consequently the whole arc a b v x 

 142 ; the distances of the directions of the muscles from the axes of the joints to 

 the distances of the line of gravity arc, according to Borelli, in the following ratio, 

 ^ the distance/ b is to the distance m b as 1 is to 8 ; ^ o v is to t v as 1 to 6 ; \ k d 

 is to p d as 1 to 3 ; and t v to b m as 3 to 4 ; hence he derived certain proportions, 

 from which he estimated that the extensor muscles of the leg, to sustain this weight, 

 exerted a force = 6032 Ibs., being more then fifty times the weight. 



