238 ' Buchanan 



(or other arm muscles), but my records of the electrical voluntary response, 

 taken with the two muscles — those with the one giving principally a 

 rhythm of over 170 per second, those with the other giving one tliat varies 

 between 40 and 120 per second — suggest that histological investigation 

 would show that the tibres composing the masseters are much more like 

 one another than are those of the flexores digitorum, and that they are all 

 of the " quick," thick variety. I do not see why it should be necessary to 

 assume, as Piper does [(1) p. 331], that waves must travel with the same 

 speed along all the fibres of the flexors. My recently obtained records lead 

 me to expect to find fibres of different kinds in the limb muscles of man 

 just as much as they are known to occur in those of the frog. By the same 

 token I can now no longer doubt that the rhythmical electrical effects so 

 often observed in frog's muscle responding to continuous stimulation, are 

 normal, a point upon which I hesitated to express an opinion in 1901 

 [(4), p. 138]. The occasional absence of rhythmical effects with the three 

 kinds of non-discontinuous stimulation I then employed, and its universal 

 absence in veratrinised muscle, may be accounted for in a way which I hope 

 to discuss elsewhere. 



VI. The Reflex Electrical Response in Max. 

 When the median nerve is stimulated by a single strong break induc- 

 tion shock while the flexor muscles in the lower arm are connected with 

 the capillary electrometer in the usual way (p. 221), the meniscus begins to 

 inscribe a curve on the plate about ocr later. It indicates that the proximal 

 contact and then the distal became each in turn negative to the other, and 

 that at the end of about a hundredth of a second, although there was slight 

 persistent relative distal-contact negativity, the effect of the direct stimulus 

 was nearly over ; and that then, some Ave or six hundredths of a second 

 later, the proximal contact and then the distal each became negative in turn, 

 three or four times in succession, but by a very much smaller amount than 

 before. In view of the records obtained when the intact mixed nerve 

 supplying the gastrocnemius of the frog is stimulated by a break induction 

 shock, which I have recently published [(10), ffgs. 1, 2, 3], I cannot help 

 regarding the second effect as a reflex effect, i. e. as the effect produced by 

 the artiflcial stimulus on afferent flbres, and only on the muscle after the 

 intervention of the central nervous system. Fig. 9 shows one such response. 

 The second effect, lasting some three or four hundredths of a second, only 

 made its appearance when there was a core in the primary coil, but it then 

 appeared (in the one person so far who has been always successful in apply- 

 ing the small exciting electrodes used, to the only place on his arm which 

 will serve to produce the direct response, and therefore the same person 

 who supplied the two records reproduced in ffg. 6) with the secondary coil 

 at 7000, there being as usual only one Daniell in the primary circuit. The 

 six records in which the second effect is seen, some of them taken on one 

 day and some on another, all show that it occurred at almost precisely the 



