FUNCTION IN PLANT LIFE 41 



The two vegetables in question are shown in Figs. 20 and 

 21. Steel darning-needles were again used, and by means 

 of these the zinc of one dry cell was connected with the 

 root and the carbon with the foliage end of A (Fig. 20), 

 while in the case of B (Fig. 21) the arrangement was carbon 

 to root and zinc to foliage end. Both were then left in a 

 room in a weak diffused light for five days and then 

 sketched. 



The drawings are explanatory in themselves, but it is 

 worthy of remark that A gave evidence of growth within 

 twenty-four hours under what may be termed natural 

 stimulus, while, though it cannot be positively asserted 

 that in B there was a retarding influence, it appeared that 

 growth was not stimulated. This, in a measure at all 

 events, proves my point that the value of electrical stimulus 

 is largely dependent upon sign of current, and lends colour 

 to the suggestion that the employment of low electromotive 

 forces in agriculture and floriculture is in harmony with 

 natural laws. 



