642 Prof. W. M. Thornton. Opj^osite Electrification [June 17, 



the positive. This reversal is no doubt accompanied by marked changes in 

 the protoplasm. In the case of an unclassified non-motile bacillus, in the 

 laboratory of the University of Durham College of Medicine, isolated from 

 a scarlet fever patient, a most active migration to the negative was 

 obtained, which, tested by samples from the same agar tube kept after 

 incubation in a cool place, lasted for about ten days, when it reversed. No 

 further observations were possible on this organism because it soon after 

 died out. 



Euss,* working with weak voltage gradients, small currents and many 

 hours' exposure, has recently found some bacteria to migrate to the positive 

 pole, others to the negative. In view of the present experiments the former 

 may be attributed to either motile response to stimulus, or the forced move- 

 ment of organisms of which the charge had been reversed by prolonged action 

 of the solution. 



With regard to the movement of growing plants, Brunchhorstf found 

 that roots extending into water through ,which a moderate current was passed 

 bent towards the negative, but when the current was strong to the positive. 

 He regarded the latter effect as secondary and due to electrolytic action. 

 Ewart and BaylissJ regard it as stimulatory. They apparently agree that, with 

 moderate currents, the movement to the negative is a response to stimulation. 



Jost§ notes that " roots which in the strong current exhibit positive 

 curvature always die, not only on the positive side but altogether, at the 

 latest after 24 hours. The negative curvature appears to be genuine stimula- 

 tion, with the root apex acting as the organ of perception." Letellieril also 

 observed curvature of growing roots towards the negative pole. The 

 sporangiophore of Fhycomijces was found by HeglerIF to bend towards the 

 negative pole under the influence of Hertzian radiation. 



From tlie difficulty experienced in working with motile organisms it was 

 decided tliat although there was cumulative evidence that the difference 

 between the animal and vegetable reaction was real, a crucial test could only 

 be made with non-motile cells of either kind, the animal cells fresh from the 

 animal, the vegetable cells from an active growth. 



f). Blood Corpuscles and Yeast. — Human blood corpuscles satisfy the coiuli- 



tions in every way. They are readily obtained fresh and, containing a high 



percentage of salts, arc not too sensitive to external influences. At first it 



* C. RiiHs, 'Roy. Soc. I'roc.,' l!)Oi), vol. 81, ]). .314. 



t ' Ber. a. bot. Gcs.,' 188 1, p. ^07. 



X ' Roy. Soc. Proc.,' B, 1905, vol. 77, j). 0.3. 



§ ' riant PliyHiology ' (trans. Harvey (iib.soii), ]!)<)7, p. 481. 



II 'Bull, dc la Soc. bot. de France,' 1899, vol. 6, j). 11. 



IT ' Vi^liandlg. d. Gen. deuts(;licr Naturf. Aorzte in Hallo,' 1891. 



