APPLICATIONS OF PHYSIOLOGY TO MEDICINE. 65 



The production of severe pain from a small amount of 

 skeletal muscle working with its blood supply cut off recalls 

 the agonizing pain excited by excessive contraction of a 

 small amount of unstriped muscle in a bit of bile duct in 

 gall-stone colic, or of ureter in renal colic, etc. Of course 

 it does not follow that the mechanism of pain production 

 is similar in the two kinds of muscle — the unstriated and 

 the striated. 



Observations on the Abductor Indicis Muscle. 



Experiments with the abductor indicis muscle gave results 

 essentially similar to those described above. For example, in 

 an experiment when a certain strength of elastic band was 

 used to resist the abduction movement, a series of about 

 240 movements could be carried out in the normal state at 

 the rate of one per second before the " fatigue " point was 

 reached — that is, the point where any abduction movement 

 failed to occur against the resistance of the band; this was 

 attended by only slight discomfort and aching — where the 

 latter was present at all. In the ischaemic hand the fatigue 

 point was reached at about one hundred contractions — that 

 is, in less than two minutes, as compared with four minutes 

 in the normal state ; this was attended by pain, which spread 

 more or less over the dorsum of the hand, though most sharply 

 felt in the working muscle. Stoppage of the efforts at abduc- 

 tion for a minute did not lead to removal of the pain, but the 

 latter was promptly relieved by re-establishment of the circu- 

 lation; contractile power recovered much more slowly, and 

 was more easily fatigued subsequently. Some minutes later 

 the hand was again rendered ischaemic, and kept in that 

 condition with quiescent muscles for ten minutes ; the hand 

 became cold, but there was no pain, simple ischaemia having, 

 as described above, no appreciable effect in this respect. 

 Abduction movements of the index finger were then per- 

 formed as before ; there was painful fatigue after about 

 sixty- five movements; the pain was removed as before by 

 readmission of the blood. The usual well-known flushing 

 occurred after the period of ischaemia ; sensations of tingling 

 gradually developed somewhat later. 



Effects of Continuous Muscular Tension. 

 Experiments were also performed with the middle finger 

 flexor muscle kept voluntarily contracted to sustain the ergo- 

 graph weight at a certain level instead of making a series of 

 consecutive lifting efforts as already described ; graphic 

 records of the behaviour of the muscle were made. Con- 

 tinuous motor effect failed to preserve the initial level 

 beyond a certain time, which varied according to the weight 

 employed, etc. ; then came a general progressive decline, 

 varied by minor irregularities in the slope of the tracing, until 

 alter a time the weight sank back to the resting position. 

 This " fatigue " is attended by comparatively little subjective 

 disturbance, even in the ischaemic arm. There was disincli- 

 nation to keep up the tension of the muscle, which seems to 

 need more and more voluntary effort, with some discomfort 

 and aching — the latter felt chiefly in the upper arm and the 

 finger — probably attributable not to the muscle itself but to 



