352 ELECTRO-PHYSIOLOGY CHAP. 



stimulation of the muscle. Then, on subtracting the period of 

 nervous conductivity from the latent period of the negative 

 variation, as observed with indirect excitation of the muscle, the 

 remainder will again be the excitation period of the nerve end- 

 organ. Certain observations of Tigerstedt may be interpreted in 

 the same sense, showing that in direct excitation of non-curarised 

 muscle, maximal twitches may sometimes appear with sub- 

 maximal strength of stimulus, in which the latent period is to a 

 marked degree more extended than it would be in maximal 

 stimulation. Again, twitches of medium and minimal height are 

 distinguished in non-curarised muscles by a longer latency than 

 the corresponding twitches of curarised muscles. 



Hoisholt (60) subsequently disputed the justice of Bernstein's 

 conclusions, on the strength of experiments performed under 

 Kuhne's direction. He equally observed (on sartorius and gracilis) 

 a much shorter latent period on stimulating the richly innervated 

 muscle-substance near the hilus, than with excitation of the 

 ingoing nerve-trunk at the same point ; but found, on the other 

 hand, with direct stimulation of the non-innervated terminal 

 sections of the muscle, that there was not merely an equal but 

 even a far more prolonged latent period than with indirect 

 excitation of the nerve. Hoisholt believed himself able to explain 

 these facts by summation of stimuli in the muscle and intramuscular 

 nerves; against w 7 hich Boruttau (60), on the strength of his 

 experiments, urged the validity of the first view, confirming with 

 supramaximal excitation the difference, as found by Bernstein, 

 for parallel-fibred muscle also, on stimulating it first indirectly, 

 and then from the nerve-free end. The latent period was 

 invariably shorter in the latter case. L. Asher (60) objected 

 to this, that a supramaximal stimulus cannot be sufficiently 

 localised to the non-innervated end of the muscle. At Kuhne's 

 instigation, Asher employed a new method in which parts of the 

 muscle, free from, and containing, nerves, should twitch separately, 

 and describe a curve under absolutely parallel conditions. In the 

 successful experiments, which were not numerous owing to the 

 shortness of the bits of muscle employed (these being hung parallel 

 with, and close to, one another), and consequent difficulties of 

 experimenting, the two curves fully correspond at the initial 

 point, and exhibit the same latent period. In spite of this, the 

 protracted latency on stimulating the nerve-trunk demands farther 



