402 



PROF. TH. W. ENGELMANN. 



continued to flow, and finally came to completely resemble 

 them. Where the lumps are formed the finer threads become 

 broken through, and in such places the thickenings are quickly 

 drawn out again into threads either from one or both sides.'' 



Fig. 4. — Cells from the stamiual hairs of Tradescantia (after Kiihne.) 

 A. Fresh, in water. B. The same cell after slight local electrical stimu- 

 lation, a — b. The region stimulated, c. Clumps and nobs of contracted 

 protoplasm. 



The rotating protoplasm of Chara and Vallisneria cells, when 

 excited simultaneously at all points, shows a slowing or stopping 

 of the movement.^ 



After this, if the excitation is sufficient, it draws itself up 



' Becquerel, 'Compt.' rend.,' ii, p. 787, 1837. Jiirgensen, 'Stud, d- 

 physiol. Instit. zu Breslau,' 1 Heft, p. 99, 1861. Velten, ' Sitzsber. d. Wiener 

 Mathera. -Physiol. Ci.,' Ixxiii, p. 350, et seq., 1876. 



