CYCLOSIS OF PROTOPLASM 



69 c 



placed with a drop of water under thin glass ; and it will generally 

 be found advantageous to use a ^-inch with the 12 or the 18 eye- 

 piece objective with an achromatic condenser. The nature of 

 the movement in the hairs of different species is far from being 

 uniform. In some instances, the currents pass in single lines 

 along the entire length of the cells, as in the hairs from the filaments 

 of Tradescantia virginicd, or Virginian spiderwort (fig. 528, A) ; in 

 others there are several such cur-^ 

 rents 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 reticulations 

 of which change their position at 

 short intervals, as in the hairs of 

 Glaucium luteum ; whilst there 

 are cases in w r hich the current 

 flows in a sluggish uniformly 

 moving sheet or layer. Where 

 several distinct currents exist in 

 one cell, they are all found to 

 have one common point of depar- 

 ture and return, namely, the 

 nucleus (B, a), from which it 

 seems fairly to be inferred that 

 this body is the centre of the 

 vital activity of the cell. In all 

 cases in which the cyclosis is 

 seen in the hairs of a plant, the 

 cells of the epiderm also display 

 it, provided that their walls are 

 not so opaque or so strongly 

 marked as to prevent the move- 

 ment from being distinguished. 

 The epiderm may be most readily 

 torn off from the stalk or the 

 midrib of the leaf, and must 

 then be examined as speedily as 

 possible, since it loses its vitality 

 when thus detached much sooner 

 than do the hairs. Even when 

 no obvious movement of particles 



FIG. 528. Rotation of fluid in hairs of 

 Tradescantia virginica: A, portion of 

 epiderm with hair attached ; a, b, c, 

 successive cells of the hair ; d, cells of 

 the epiderm ; e, stomate. B, joints of a 

 beaded hair showing several currents ; 

 a, nucleus. 



is to be seen, the existence of 

 a cyclosis may be concluded from the peculiar arrangement of the 

 molecules of the protoplasm, which are remarkable for their high 

 refractive power, and which, when arranged in a ' moving train,' 

 appeal- as bright lines across the cell ; and these lines, on being 

 carefully watched, are seen to alter their relative positions. The 

 leaf of the common Plantago (plantain) furnishes an excellent example 

 of cyclosis, the movement being distinguishable at the same time 

 both in the cells and in the hairs of the epiderm torn from its stalk 



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