126 



THE HUMAN MOTOR 



Desaguliers (loc. cit.). Schultze ( J ) and Grehant ( 2 ) obtained an 

 average of 45 kilogrammes as the force of traction with both hands. 



The muscles of the neck can withstand up to 200 kilogrammes 

 without bending, and on an average 150 kilogrammes. Qu6telet 

 (loc. cit.) meas- 

 ured the "renal 

 force" by 

 means of " Reg- 

 nier's" dynamo- 

 meter (see 206) 

 the instrument 

 is placed be- 

 tween the feet of 

 the subject and 

 fixed to the 

 ground ; he 

 pulls the other 

 extremity (fig. 

 128) first bend- 

 ing and then 

 straightening 

 himself. By ex- 

 periments on 

 thousands of 

 people Quetelet 

 determined the 

 renal force for 

 various ages and 

 sexes. The re- 

 sults between 

 the ages of 6 and 

 60 are shewn in 

 fig. 129. The 

 average for an 

 adult is 150 

 kilogrammes in 

 man, and 78 

 kilogrammes in 

 woman. Senile 



/4 16 18 ?0 25 40 60 



67 8 3 W 12 



FIG. 129. 



Variations of renal force with age. 



decay is observ- 

 able from about 40 years. 



The relative difference between the sexes is shown by the 

 development of the muscles, which are larger in man than in 

 woman, and also have a better functional adaptation. The same 



(*) Schultze (Bibliotheque Britannique, vol. Ivi). 

 () Grehant (Comptes Rendus Biologie, 1897). 



