BIOELECTRIC rHENO.MEXA 325 



in such cases the internal contractile mechanism of the 

 cell is incapacitated; and apparently this may occur 

 without disturbing the primary processes of stimulation 

 and conduction, which depend on surface-changes 

 associated with the bioelectric variation. Such a 

 dissociation of conduction and excitation from contrac- 

 tion is also seen during the water-rigor of muscles; at a 

 certain stage of water-rigor a muscle will conduct 

 excitation without contracting.^ Under normal condi- 

 tions, however, the electromotor variation and the 

 functional process exhibit close parallelism. The inverse 

 type of case, i.e., where a muscle contracts or nerve 

 conducts without exhibiting a bioelectric variation, does 

 not seem to occur. ^ The electromotor variation seems 

 to be inseparable from the process of stimulation. It 

 may be prevented from appearing (by anaesthesia, etc.), 

 but in that case all of the other manifestations of stimula- 

 tion are also prevented. Such facts again indicate the 

 primary and controlling role of the electromotor varia- 

 tions in cell-activities. 



TIME RELATIONS OF BIOELECTRIC VARIATIONS 



We have seen that the time occupied by a single 

 electromotor variation (i.e., of the unsummated etlect 

 resulting from a single stimulus) varies characteristically 



» Biedermann, Sitziingsberichte der Akadcmie, Wicn., XCVII (1888), 

 Part III, p. loi; cf. also Overton, Arch. ges. Physiol., XCII (1902), 146; 

 he finds that frog's muscle immersed in 0.2 per cent NaCl loses con- 

 tractility while still retaining irritability and conductivity. Cf. also 

 Hartl, Engelmann's Archiv f. Physiol. (1904), p. 80. Robertson has 

 observed the same phenomenon in the intestine of the Australian blow- 

 fly after bathing in CaCh solution (Ergebnissc dcr Physiol, X I1910I, 305). 



»Cf. Lucas' discussion of this question in his Croonian Lecture, 

 op cit,, p. 502. 



