CHAP. XII. §. n. IN BOOTS DURING VEGETATION. 173 



in which it would appear that an acid is formed 

 during the germination of the seeds. 



If any difficulty occurred in pointing out the 

 electro-positive element in the leaves, the same dif- 

 ficulty meets us here, and the question arises, Are 

 not the results which were obtained with the galva- 

 nometer rather the results of secondary reactions, in 

 the majority of instances, than those of the primary 

 actions (the normal results), and which I obtained 

 but in a few instances, viz. when the sap indicated a 

 positive condition? The very circumstance of an 

 acid being secreted or formed at the root would 

 indicate that an electro-positive element must have 

 appeared somewhere, and why not, it may be asked, 

 might it not have been absorbed by the plant? 

 Might not those instances in which I obtained no 

 effect upon the needle arise from the two currents 

 being so equally balanced, that the resulting effect 

 ■ upon the needle was null ? In judging of the effect 

 obtained by the needle', it appears to me that very 

 erroneous conclusions would be arrived at, if the 

 greatest amount of effect were to decide in each 

 case ; we must take into consideration the assumed 

 origin of the current, and see whether the effect 

 bears any proportion to the amount of force in 



' There is also something to be ohserved in the motion of the 

 needle, which can only he obtained by practice, when judging of 

 slight effects. Far more correct results are indicated when the 

 needle moves steadily and in a constant and definite manner, 

 than when a sudden and great amount of motion is obtained. 



