14 BOTANY. 



(/) The passage from the condition in the last examples (the so- 

 called circulation of protoplasm) is an easy one to the cases where the 

 whole mass of protoplasm moves along the cell-wall as a broad stream, 

 passing up one side and down the other (the so-called rotation of pro- 

 toplasm). Common and well-known examples of this kind of mass-move- 

 ment occur in Chara, Naias, and Vcdlisneria. It may also (on the 

 authority of Meyen) be studied in the root-hairs of many land plants — 

 e.g., of Impntiens BalmmirM, Vicia faba, Ipomma purpurea, OiLCvmis, 

 Cucurbita, Ranunculus sceleratus, and Marchantia polymorpha. 



Note. — In the study of the structures treated of in Chapters I to V 

 inclusive, the student will do well to consult a recent laboratory man- 

 ual — "Botanical Micro-Chemistry," by V. A. Poulsen (William Tre- 

 lease, 1884). 



