ORGANS OF CIRCULATION. 



and the water plantain, are the plants that have been 

 most commonly selected for examining the 'rotatory 

 currents. I have taken the following figure of the 

 currents in the water plantain, from M. Schultz. 



The arrows show the direction of the currents ; a, a, the cellular 

 tissue ; b, b, b, the vessels in which the currenta-take place, whose 

 direction is pointed out by the arrows. 



Professor Link, shrewdly suspecting that the expe- 

 riments usually performed by watering plants with 

 coloured fluids are inaccurate, in consequence of the 

 colouring matter being only mechanically, and not che- 

 mically mixed, had recourse to the ingenious contrivance 



