200 ELECTRO-PHYSIOLOOY CHAP. 



into contact with the muscle in such a way that their line of con- 

 nection cut transversely across the muscle-fibres, so that a current 

 passing through the contacts must traverse the muscle mainly 

 in a transverse direction. Yet it is almost self-evident that 

 under these conditions, even with the most exact transverse 

 passage, there must also be longitudinal lines of current. It 

 would then depend merely upon the strength of stimulus 

 whether these were able to provoke an excitation. Sachs con- 

 tended that the strength of current, which is just effective in his 

 experiments, acted through the lines of connection between the 

 two electrodes only, but this, as was justly observed by Leicher 

 (16), could only occur under certain non-existent premises. 



A more satisfactory method, invented by Matteucci in 1838, 

 and then applied to nerve by Luchsinger (17) at Hermann's in- 

 stigation, consists in plunging the object to be traversed by the 

 current (nerve or muscle) into an indifferent conducting fluid, 

 which the exciting electrodes also dip into. In this case the 

 muscle, which lies at right angles to the lines between the elec- 

 trodes, is entirely, or at least mainly, traversed by vertical lines 

 of current only entirely when the electrodes are flat or linear, 

 mainly when they are punctiform. Tschirjew (18), who used 

 this method, found that greater intensity of current is required 

 on exciting the muscle transversely than in longitudinal excita- 

 tion, but he believed notwithstanding (taking into account 

 Hermann's statement that the resistance of the muscle 

 is much greater 49 times in the transverse than in the 

 longitudinal direction, so that a greater fraction of the cur- 

 rent must pass through the muscle with longitudinal than 

 with transverse stimulation), that muscle is more excitable to 

 transverse than to longitudinal passage of current. Both this 

 experiment, however, and those which Giuffre, Albrecht, and 

 Meyer (19) worked out under Hermann's direction, present 

 weighty experimental objections, as Hermann himself pointed 

 out. Tschirjew either placed the excised muscle in the excitation- 

 trough, with silk thread attached to both ends, connecting them 

 with a lever, or employed minute quadrants of muscle ; while 

 Giuffre tried to avoid the difficulties due to irregularities of form 

 in the ends of the muscle (sartorius) by dipping only the portion 

 with- parallel fibres, which he marked off with artificial transverse 

 sections, into the fluid. Since, however, as will be shown, 



