IV] STRUCTURE OF THE CELL 163 



many of their most striking features they may be admirably 

 simulated by the diffusion of salts in a colloid medium; others 

 again, like Gallardo* and Hartog, and Rhumbler (in his earher 

 papers) f, insist on their resemblance to the phenomena of 

 electricity and magnetism J ; while Hartog beUeves that the force 

 in question is only analogous to these, and has a specific identity 

 of its own §. All these conflicting views are of secondary import- 

 ance, so long as we seek only to account for certain configurations 

 which reveal the direction, rather than the nature, of a force. 

 One and the same system of Hues of force may appear in a field 

 of magnetic or of electrical energy, of the osmotic energy of 

 diffusion, of the gravitational energy of a flowing stream. In short, 

 we may expect to learn something of the pure or abstract dynamics, 

 long before we can deal with the special physics of the cell. For 

 indeed (as Maillard has suggested), just as uniform expansion 

 about a single centre, to whatsoever physical cause it may be due 

 will lead to the configuration of a sphere, so will any two centres 

 or foci of potential (of whatsoever kind) lead to the configurations 

 with which Faraday made us familiar under the name of "lines 

 of force||"; and this is as much as to say that the phenomenon, 



tischen Kraftliniensystemen unci Zelltheilungsfiguren, Arch. f. Entw. Mech. xv, 

 p. 482, 1903. 



* Gallardo, A., Essai d'interijretation des figures caryocinetiques, Anales del 

 Miiseo de Buenos-Aires (2), ii, 1896; La division de la cellule, phenoraene bipolaire 

 de caractere electro-colloidal. Arch. f. Entw. Mech. xxviii, 1909, etc. 



t Arch. f. Entw. Mech. m, iv, 1896-97. 



J On various theories of the mechanism of mitosis, see (e.g.) Wilson, The Cell 

 in Development, etc., pp. 100-114; Meves, Zelltheilung, in Merkel u. Bonnet's 

 Ergebnisse der Anatomic, etc., vii, viii, 1897-8; Ida H. Hyde, Amer. Journ. 

 of Physiol. XII, pp. 241-275, 1905; and especially Prenant, A., Theories et inter- 

 pretations physiques de la mitose, J. de VAnat. et Physiol, xlvi, pp. 511-578, 1910. 



§ Hartog, M., Une force nouvelle: le mitokinetisme, C.R. 11 Juli, 1910; 

 Mitokinetism in the Mitotic Spindle and in the Polyasters, Arch. f. Entw. Mech. 

 xxvn, pp. 141-145, 1909; cf. ibid. XL, pp. 33-64, 1914. Cf. also Hartog's papers 

 in Proc. R. S. (B), lxxvi, 1905; Science Progress (n. s.), i, 1907; Riv. di Scienza, 

 II, 1908; C. R. Assoc.fr. pour VAvancem. des Sc. 1914, etc. 



II The configurations, as obtained by the usual experimental methods, were 

 of course known long before Faraday's day, and constituted the "convergent and 

 divergent magnetic curves" of eighteenth century mathematicians. As LesUe 

 said, in 1821, they were "regarded with wonder by a certain class of dreaming 

 philosophers, who did not hesitate to consider them as the actual traces of an 

 invisible fluid, perpetually circulating between the poles of the magnet." Faraday's 

 great advance was to interpret them as indications of stress in a medium, — of 



11—2 



