Hairs of Plants. 113 



"be viewed without disturbing them, by using a low power, and 

 illuminating them as an opaque object. They will be seen to 

 be tubes terminating in globular beads, and more or less filled 

 with, a bright-coloured fluid. A few of the hairs may then be 

 cut off with a fine, sharp pair of scissors, taking a delicate slice 

 of the cuticle of the corolla with them. These hairs, examined 

 under a power of from 200 to 1000 linear, will be found covered 

 with minute elevations all up their tubes and over the expan- 

 sion at the top. Although the terms cuticle and epidermis are 

 commonly applied to the whole cell- wall of a hair, it will be 

 found that a true epidermis, or outer covering, may be sepa- 

 rated by acids from the real skin, if we may use the term. In 

 the case of these hairs, nature seems to have blown out the 

 true epidermis in little bubbles of elongated form, and hence 

 the irregular appearance which their surface presents. Some 

 of these snapdragon corolla hairs are spindle-shaped, and 

 blown out with more or less irregularity. They are all interest- 

 ing microscopic objects, and the splendid yellow colour of their 

 contents does not seem to be injured by glycerine jelly. Another 

 pleasing object will be found on the stems of the pretty wild 

 flower, " Herb Robert," the hairs of which have exquisite ruby 

 balls at their tips. 



The phenomena of cell rotation may be seen in hairs, and 

 Mr. Wenham has traced it in a great variety of plants. It 

 requires careful illumination for its display, and a higher 

 power than suffices for showing the movement of the coloured 

 sap globules in Anacharis or Yalisneria. The hairs to be 

 examined should be removed without injuring them, by tear- 

 ing off a portion of the cuticle from which they spring. They 

 should be immersed in a drop of water, and, if necessary ^ 

 slightly warmed by blowing hot air upon the covering glass, 

 which may be effected by means of a glass tube heated by a, 

 spirit lamp. Dr. Carpenter says fr the nature of the movement 

 in the hairs of different species of plants 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 the Tradescantia Virginica, or Virginian spider- 

 wort. In others there are several such currents which retain 

 their distinctness, as in the jointed hairs from the calyx of the- 

 same plant. In others, again, the streams coalesce into a net- 

 work, the reticulations 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. When several distinct currents exist 

 in one cell, they are all found to have one common point of 

 departure and return, namely, the (e nucleus," from which it 

 seems fairly to be inferred that this body is the centre of the 



VOL. VIII. — NO. II. I 



