498 APPENDIX 



tuning-fork also writing its vibrations), using the platinum electrode. 

 The lever nearer the electrode will be pushed upward by the contraction 

 wave first, and the other lever will rise a few hundredths of a second 

 later. Drop from the beginnings of the two myograms perpendicular 

 lines to the tuning-fork's record, and count the number of double fork- 

 vibrations between the two lines. This number will be the time in 

 hundredths of a second required by the contraction-wave to travel be- 

 tween the -cork stilts. Measure the length of the muscle between these 

 two points. Reduce these millimeters per hundredths of a second to 

 meters per second and the result is the speed of the contraction-wave 

 in the particular case studied. 



The contraction-wave is to be discriminated from the action-current. 

 The latter is electrical and perhaps an extraneous phenomenon, while 

 the contraction-wave is the actual physical thickening of the muscle 

 which progresses in the likeness of a wave through the muscle at a 

 definite rate. This thickening begins at any point in a muscle where 

 a stimulus is applied to it, and divides and moves in both directions up 

 and down the muscle. It progresses at the rate of about 3 m. per second 

 in the cross-striated muscles of the frog, and faster in those of homo- 

 therms. The wave is about 30 cm. long, that is, were a muscle long 

 enough, at intervals of 30 cm. along the muscle the thickening or crest 

 of the wave would be seen simultaneously. In the red cross-striated 

 muscle of the rabbit Rollett found the contraction-wave rate to be about 

 3.4 m., but in the. white fibers it may go as fast as 11 m.; in human mus- 

 cle the speed is (Hermann) from 10 to 13 m. per second. This pro- 

 gressive wave of thickening of the whole muscle is of course dependent 

 directly on the thickening of the individual striped fibers in the well- 

 known way. 



In smooth muscle, according to Engelmann, the rate is only about 

 0.025 m. per second, while in the frog's heart ventricle (the muscle 

 being, so to say, intermediate in character) the rate is (Waller) about 

 0.1 m. per second. 



Expt. 59. Polar Stimulation. (Apparatus: Sartorius muscle, rheo- 

 cord, simple key, and dry-cell.) Slit up the sartorius about one-third its 

 length and lay it on the glass plate. Have the plate and the muscle 

 comparatively dry. Place the anode on the left-hand side of the muscle, 

 the cathode on the right-hand leg. Close the key, hold it three seconds 

 and then open it. On the make, the right side of the muscle (cathode) 

 contracts and on the break the left (anode) i. e., application of a mod- 

 erate galvanic current causes stimulation at the cathode, and removal 

 of the current stimulation at the anode. 



Expt. 60. Physiological Anode and Cathode. (Apparatus: Rectus 

 abdominis muscle of frog, rheocord, simple key, and dry-cell.) Connect 

 a dry cell with a rheocord and key in the usual way. Remove the rectus 

 abdominis muscle and lay it well stretched out longitudinally on the glass 

 plate with weights if necessary. Place the anode from the rheocord on 

 one end of the muscle and the cathode on the other. Using a very faint 



