14 BOTANY. 



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

 called circulation of protoplasm) Js 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 Chora, Naias, and Vallisnerin. It may also (on the 

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

 e.g., of Impatiens Balsamina, Vicia fdba, Ipnmma purpurea, Cucumis, 

 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," l)y V. A. PoulsoiL (William Tre- 

 lease, 1884). 



