CYCLOSIS IN NITELLA. 



339 



detached, the circulation resumes its regularity, no part of either 

 current passing the boundary. In the young cells, however, the 

 rotation may be seen before the granular lining is formed. The 

 rate of the movement is affected by anything that influences the 

 vital activity of the Plant ; thus, it is accelerated by moderate 

 warmth, whilst it is retarded by cold ; and it may be at once 



Fig. 158. 



Nitella flexilis .—a, stem r and branches of the natural size; 

 a, b, c, d, four verticils of branches issuing from the stem ; 

 e, f, subdivision of the branches ;— b, portion of the stem and 

 branches enlarged ; a, b, joints of stem ; c, d, verticils ; e, f, new- 

 cells sprouting from the sides of the branches ; g, h, newcells 

 sprouting at the extremities of the branches. 



checked by a slight electric discharge through the plant. The 

 moving globules, "which consist of starchy matter, are of various 

 sizes ; being sometimes very small and of definite figure, whilst in 

 other instances they are seen as large irregular masses, which appear 



z 2 



