MEASUREMENT OF MUSCLE-FORCE IN MEN. 



69 



Fig. 24. Dyxamo.mkter. 



ill his results as regards the calf-muscles, found much 

 lower fiofures. But in this case, errors in calculation 

 evidently occurred, and explain the difference. 



To determine the muscles of the forearm which 

 bend the lingers, a dynamometer, as represented in fig. 

 24, may be used. The strong spring handle of steel. A, 

 being grasped with both 

 hands, is pressed together 

 with the whole strength. 

 The alteration in the 

 curves which is effected 

 in the instrument at the 

 points d and d\ is trans- 

 mitted by the lever a b a' 

 to the index c, which indi- 

 cates in kilogrammes the amount of force exercised on 

 the graduated scale B. A somewhat elaborate calcu- 

 lation would be necessary to find from this the absolute 

 force of the muscles employed. If, however, the force 

 which men are generally able to exercise with their 

 hands is known, tlie apparatus may be conveniently used 

 to detect occasional variations, such as occur, for in- 

 stance, at the commencement of lameness and other 

 diseases of the locomotive apparatus. The dynamo- 

 meter has, therefore, become of importance in the in- 

 vestiofation of diseases. 



7. We have already observed that a muscle during 

 a single pulsation attains its full force, not at once, but 

 only gradually, and we have seen the way in which the 

 periods necessary for attaining the different values of 

 the energy may be determined by means of the electric 

 method of measuring time. If the muscle contracts 

 freelv, little or no weight being attached, it exhibits 



