62 J. A. MacWILLIAM AND W. J. WEBSTER. 



recognizable in the states of rest and activity are examined 

 and brought into relation with other functional conditions, 

 such as changes in contractile power, etc. 



MetJiods of Experiment. 



The forearm was investigated (a) while the normal circula- 

 tion was going on, and (6) when the blood supply was stopped, 

 the limb either retaining its blood in a stationary condition or 

 being rendered exsanguine before the circulation was arrested 

 — that is, the " congested arm " and the " ischaemic " arm 

 were examined with arrested cii'culation. The circulation 

 was stopped by a blood pressure armlet applied to the upper 

 arm, which was rapidly pumped up to a constricting pressure 

 much above what was necessary to produce arterial oblitera- 

 tion in the particular individual examined — that is, an armlet 

 pressure largely exceeding the systolic pressure. When this 

 was done in the usual way, as for the measurement of systolic 

 blood pressure, a " congested arm " was obtained containing 

 a large amount of stationary blood shut off from the general 

 circulation, the veins becoming prominent and tense. To 

 obtain the bloodless or ischaemic arm an elastic bandage was 

 first applied to the hand and arm, and removed after the 

 armlet had been pumped up as described. 



In the congested arm the sensory phenomena are naturally 

 complex, being partly attributable to conditions attendant on 

 the arrest of the circulation as influencing the muscles, etc., 

 and partly to the discomfort caused by the venous turgescence. 

 To avoid the latter complication the metliod of the ischaem'c 

 arm is employed; the sensations induced by muscular 

 activity in presence of acute want of blood can then be 

 examined. 



Under these conditions muscular action was tested in 

 various ways. Graphic records of the flexor muscle of the 

 middle finger were made by means of a Mosso's ergograpb, 

 the voluntary flexion movements being made in regular 

 series — one in one second or in two seconds, etc. — timed by 

 a metronome, while the weight lifted at each contraction 

 varied in different experiments from 1 to 3 kg. The be- 

 haviour of the muscle in different conditions, the amounts of 

 mechanical work done as measured in kilogram- metres, the 

 development of fatigue, etc., were graphically recorded, while 

 the sensations associated with different phases were noted. 

 The results as regards fatigue, etc., will be described else- 

 where, the present communication having to do with the 

 sensory phenomena. 



Another method is to use a series of grasping movements 

 with the hand, bringing them to bear on a dynamometer or a 

 dynamograph; this method is in some respects less precise 

 than the preceding. 



Another mode of experiment was to use the abductor 

 indicis muscle, working against the resistance of a strong 

 elastic band embracing the fingers ; successive abduction 

 movements of the fingers were then made in regular series ; 

 only the hand was rendered ischaemic in this case, the armlet 

 being applied to the forearm. The hand was supported on a 



