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THE POPULAR SCIENCE MONTHLY. 



(Fig. 9). The hairs on the young leaves of violets and on common red 

 clover exhibit the same sort of a stream moving in much the same way 

 (Figs. 10 and 11). 



The unicellular hairs of the common morning-glory present a dif- 

 ferent phase of the same current. Here the stream is confined to the 



Fig. 9. Tip of a Hair Fig. 10. Tip of a Hair Fig. 11. Hair from Fig. 12. Hair from 

 from Evening Prim- from Violet Leaf. Red Clover. Morning GJloky, uni- 



rose. cellular. 



cell- wall most closely, but the movement is unique. The protoplasm 

 in its course is by turns contracted and expanded, giving to the whole 

 current a billowy appearance, a miniature profile of rolling waters. 

 Wave follows wave, but with no deceptive motion, for the rapidly 

 passing granules advise us that the current is strong and real under- 

 neath waves that rise and fall but never break (Fig. 12). 



