384 THE PROPERTIES OF STRIPED MUSCLE. 



wave itself led to erroneous results. Bezold 1 (1861) measured the 

 time-interval between the excitation and the beginning of response, 

 when the muscle, clamped in the middle in such a way as to prevent the 

 change of form, but not the excitation, from passing, was excited at one 

 end and observed at the other. Aeby 2 (1860) caused a muscle excited 

 at one end, to record simultaneously, on the same rapidly moving surface, 

 its thickening at two points as far removed from one another as possible ; 

 two curves being thus obtained, of which the one drawn by the lever 

 furthest removed from the exciting electrodes was a certain distance 

 behind the other in time. Both of these modes of determining the rate 

 of propagation gave results which fell short of the truth. Ten years 

 later, Bernstein 3 applied the more correct method of comparing the 

 moments at which successive waves, travelling in the same direction 

 from different points, reached a particular spot at a known distance 

 from each of them. Bernstein used muscles of which the fibres are inter- 

 rupted by tendinous insertions. Hermann, 4 criticising this, made similar 

 experiments with the sartorius, using for measurement Pouillet's 

 instead of the graphic method, and obtained a mean result of 27 

 metres per second as the rate of propagation therein. Notwithstanding 

 the disadvantages just referred to, Bernstein's estimate, although it 

 closely approximated to that of Hermann, was a little higher, so that 

 we may accept the statement usually made, that the rate in frog 

 muscles is about 3 metres per second, as correct. In mammalian 

 muscle the rate is, as a rule, much greater than this ; the elaborate 

 investigations of Eollett 5 show that, although it is not more than 

 34 metres in the red muscles of the rabbit, the rate of propagation 

 may be as much as 11 metres per second in the white. The duration of 

 the twitch is correspondingly longer in the red muscle than in the pale, 

 the observations of Kronecker and Stirling 6 having shown that it is 

 three times as long in the one as in the other. Cash 7 has demonstrated 

 that similar, though less considerable, differences in duration present 

 themselves in the different muscles of the frog, a single twitch of the 

 gastrocnemius, e.g., lasting 012 sec., while that of the hyoglossus may 

 last as long as 0'3 sec. 



Conduction of slow waves in transversely striated muscle. On 

 this subject very little is definitely known, for the existence of slow waves has 

 only been established as regards muscles which are under abnormal conditions. 

 They are most readily observed in insect muscles. Rollett 8 has shown that 

 in the living larva of Corethra they occur side by side with the quick 

 contractions or twitches, and may alternate with them or be interrupted 

 by them. They are therefore independent phenomena; and whereas the 

 twitch seems to be dependent on influences emanating from the nervous 

 system, predominating when the animal is most vigorous, the slow contractions 

 seem to be idiomuscular, i.e., to emanate from the muscle itself; for they 

 only begin to appear as the animal loses its vivacity and as the control 

 exercised by the nervous system is withdrawn. They persist even when death 



1 " Untersuch. ueber die elect. Erregungen von Muskeln und N erven," 1861, S. 156. 

 ~ Arch.f. PhysioL, Leipzig, 1860, S. 253 ; and "Untersuch. ueber die Fortpflanzungs- 

 geschw. der Reizung im quergest. Muskelfasern, " Braunschweig, 1863. 



3 "Untersuch. ueber den Erregungsvorgang im N erven- und Muskel-systeme," 1871, 

 S. 79. 



4 Arch. f. d. ges. PhysioL, Bonn, 1874, Bd. x. S. 48. 



5 Ibid.,' Ed. Hi. S. 224. 



6 Arch.f. PhysioL, Leipzig, 1878, S. 1. 



7 Ibid., 1880. *Loc. cit. 



