128 APPENDIX A. 



appear to have been generally neglected until 

 lately, when the re-discovery of the phenome- 

 non in other plants, has excited the attention of 

 botanists .... We shall explain the phenome- 

 non as it may be seen in the Chara with a lens 

 of about the tenth of an inch focal distance, or 

 even of less power." 



" In the genus Nitella" (a section of the 

 Chara, and which is to be preferred to the true 

 Chara, from the superior transparency of its 

 tubes) " the stems consist of single, jointed 

 tubes. At the joints of the stem are whorls of 

 branches, composed also of short tubes, in each 

 of which the same rotation of the contained fluid 

 may be seen. If an entire tube occupying the 

 space between two joints, be placed under the 

 microscope, its inner surface appears to be stud- 

 ded with minute green granules, arranged in 

 lines, which wind in a spiral direction from one 

 extremity to the other. They are studded over 

 the whole of the interior, with the exception of 

 two narrow spaces on opposite sides of the tube, 

 forming two spiral lines from end to end. The 

 globules of transparent gelatinous matter dis- 

 persed through the fluid are in constant motion, 

 being directed by a current up one side of the 

 tube, and back again by the other. The course 

 of this current is regulated by the spiral arrange- 

 ment of the granules, and it moves in opposite 



