io8 Shiro Tashiro 



This fact lead to a search for evidence of the chemical nature of 

 irritability and in a number of papers 5 it was clearly pointed out that 

 the anaesthetics were probably acting directly in a chemical manner 

 instead of indirectly, by affecting permeability, and that probably 

 the anaesthetics acted by uniting with the protoplasm where 2 usually 

 took hold. This view was strengthened by the temperature coeffi- 

 cient of conduction, which is nearly that of a chemical reaction; by 

 the importance of C>2 for artificial parthenogenesis; and by many other 

 facts some of which have recently been collected by Haberlandt, 

 Buijtendijk and others. 



Although it has been established by repeated demonstrations, that 

 the nerve does not fatigue under ordinary conditions, as measured 

 by the method used in muscular studies, yet Frohlich 6 observed that 

 the nerve undergoes certain changes by long activity. Gotch and 

 Burch discovered 7 in 1889 that if two stimuli are successively set 

 up within -%%-$ of a second, only one negative variation is produced. 

 This critical interval, or refractory period, is found to be altered by 

 temperature changes, by drugs, asphyxiation, and anaesthetics. 8 

 Thus by prolonging the refractory period by partial anaesthesia, Froh- 

 lich easily demonstrated that with a frequency of stimulation less 

 than this normal refractory period, stimulation of the attached muscle 

 no longer occurred. He interprets this as a phenomenon of fatiga- 

 bility of the nerve. Thoner's 9 observation seems to lead to a similar 

 interpretation, for he found recently that fatigability is less effec- 

 tive when the refractory period is shortened by high temperature. 

 There seems, then, to be fatigue in the nerve, but it cannot be 

 measured by an ordinary scale. 



After the complete failure of the chemical detection of CO 2 and 



6 A. P. MATHEWS: Biological bulletin, 1904-5, viii, p. 333; this Journal, 

 1904, xl, p. 455; ibid., 1905, xiv, p. 203; Biological Studies by the pupils of 

 William Sedgwick, 1906, p. 81; Journal of pharmacology and experimental 

 therapeutics, 1911, ii, p. 234. 



6 FROHLICH: Zeitschrift fur allgemeine Physiologic, 1903-4, iii, p. 445. Ibid., 



P- 75- 



7 GOTCH and BURCH: Journal of physiology, 1899, xxiv, p. 410. 



8 See TAIT and GUNN, Quarterly journal of experimental physiology, 1908, 

 i, p. 191; TAIT, ibid., 1909, ii, p. 157. 



9 THONER: Zeitschrift fur allgemeine Physiologic, 1908, viii, p. 530; ibid*, 

 1912, xiii, pp. 247, 267, 530. 



