394 



CYCLOSIS IN HAIRS OF TRADESCANTIA, ETC. 



necessary is, that the part from which the hair is gathered should 

 be in a state of vigorous growth. The Hairs should be detached 

 by tearing off, with a pair of fine-pointed forceps, the portion of 



the Cuticle from which 



Fig. 202. 



they spring; care being 

 taken not to grasp the 

 Hair itself, whereby 

 such an injury would 

 be done to it as to 

 check the movement 

 within it. The Hair 

 should then be placed 

 with a drop of water 

 under thin glass ; and 

 it will generally be 

 found advantageous to 

 use a l-8th inch Objec- 

 tive, with an Achro- 

 matic Condenser 

 having a series of dia- 

 phragms. The nature 

 of the movement in 

 the Hairs of different 

 species is far from be- 

 ing uniform. In some 

 instances, the currents 

 pass in single lines 

 along the entire length 

 of the Cells, as in the 

 Hairs from the fila- 

 ments of the Trades- 

 cantia virginica, or 

 Virginian spiderwort 

 (Fig. 202, a); in 

 others there are several 

 such currents which 

 retain their distinct- 

 ness, as in the jointed 

 Hairs of the Calyx of 

 the same plant (b^ ; 

 in others, again, the 

 streams coalesce into a 

 network, the reticula- 

 tions of which change 

 their position at short 

 intervals, as in the 

 hairs of Glaucium luteum ; whilst there are cases in which 

 the current flows in a sluggish uniformly-moving sheet or 

 layer. Where several distinct currents exist in one Cell, they are 



Rotation of fluid in Hairs of Tradescantia 

 Virginica : — a, portion of Cuticle with Hair 

 attached ; a, b, c, successive Cells of the Hair ; 

 d, Cellsj of the Cuticle ; e, Stoma :— b, joint 

 of a beaded Hair, showing several currents ; 

 a, Nucleus. 



