APPLICATIONS OF PHYSIOLOGY TO MEDICINE. 63 



table with the palmar surface downwards. Graphic records 

 can be obtained by making the movements of the finger 

 inscribe on a moving smoked paper. 



Iscliaemia of the Besting Arm. 

 In observations made by these methods it was found that 

 simple deprivation of blood in the ischaemic limb for periods 

 up to twenty minutes caused no great sensory effects, only 

 coldness in the bloodless part, with an inclination to shift the 

 position of the limb, and a certain amount of discomfort from 

 the continued constriction by the obliterating armlet; the 

 absence of pain is to be noted. 



Muscular Action in the Ischaemic Arm,, 

 Muscular action in the ischaemic limb soon becomes pain- 

 ful, and when carried to the point of " fatigue " is acutely 

 painful. "Fatigue" is indicated by inability to go on 

 executing contraction movements even of greatly reduced 

 range. This index of " fatigue " is convenient for comparing 

 the state of matters in normal and ischaemic muscles, though 

 it does not represent inability of the muscle to do more 

 mechanical work in more favourable circumstances — for 

 example, with less resistance opposing the contraction, a 

 lighter weight to lift, etc. It is a useful index of the stage 

 of enfeeblement of the voluntary contractile power with 

 which the sensory manifestations in muscles under different 

 conditions can be correlated. The actual time necessary to 

 induce fatigue and the number of movements that can be 

 executed prior to this point are of course largely influenced 

 by the weight used; with a sufficiently light weight the 

 movements can be kept up for hours without the occurrence 

 of fatigue in the normal arm while the circulation is intact. 

 Under normal conditions the phenomena of fatigue as shown 

 by ergograph records are well known. The associated 

 sensations as the fatigue point is approached take the form 

 of a sense of increased effort being necessary to raise the 

 weight even for a short distance, an increasing disinclination 

 to go on making the successive efforts, aching or dull pain in 

 the central part of the forearm, etc. We have often found 

 a certain amount of local tenderness to pressure in the 

 fatigued muscles, lasting for some little time after action has 

 been discontinued. 



In the ischaemic arm the fatigue point is reached much 

 more rapidly, often in one-half or one-third the time needed 

 in the normal arm, with a proportionate diminution in the 

 number of contractions executed, the more rapid development 

 of extensive weakening at a relatively early stage, etc. Pain 

 develops and by the time the fatigue point is reached becomes 

 severe ; further efforts at contraction movements lead to 

 distressingly acute pain and the desire for relief becomes 

 urgent, while there is a strong disinclination to attempt 

 further efforts. 



Distribution and Characters of the Pain, 

 The pain is felt over the flexor aspect of the forearm and 

 is most intense in the central part of the forearm; it is 



