in vegetable Structures. 297 



April 20. Copper surface. Cotyledons widely expanded, 

 but still yellow ; elevated one third of an inch above 

 the flannel, to which they are attached by their radicles. 

 A piece of reddened litmus paper, when brought in contact 

 with the flannel, becomes blue. 



Zinc surface. Cotyledons, in many of the seeds, not 

 even expanded : in some, and generally in those most 

 remote from the zinc, the cotyledonary leaves had become 

 expanded, and elevated about a quarter of an inch above 

 the flannel, to which they were attached by their radicles; 

 but even the most forward of these presented a far different 

 aspect to the vigorous plantules on the copper surface of 

 the compound disc. On bringing a piece of litmus paper 

 in contact with the flannel, it assumed a faint red tint. 



April 30. Copper surface. Plantules between 2 in. and 3 in. 

 in length, presenting every appearance of health and vigour, 

 in which they far exceeded those which had been growing 

 on a glass plate the same length of time. 



Zinc surface. Plantules scarcely exceeding 1 in. in 

 length : the majority had shrivelled up and died : even 

 amongst the most vigorous the cotyledonary leaves retained 

 their yellow tint, presenting a most striking contrast to 

 those vegetating on the copper surface. 



May 8. Copper surface. Plantules present every appearance 

 of perfect health : they have grown rapidly during the 

 last week ; their primordial leaves are of a deep and 

 healthy green. 



Zinc surface. Most of the plantules are withered and 

 dead. Some, however, continue to exist, scarcely exceed- 

 ing l in. or H in. in length ; their primordial leaves being 

 of a pale, unhealthy, yellowish green. 



From the results of these experiments, we are, I think, 

 authorised in believing that electric currents are not only 

 developed during germination, but that their influence is im- 

 portant, if not necessary, to the proper performance of that 

 process; for the results of M. Becquerel's experiments are 

 sufficient to demonstrate that germinating seeds expel acids 

 and attract bases, and hence bearing some resemblance to the 

 negative element of a voltaic arrangement ; whilst the actual 

 developement of electricity during germination has been fully 

 proved by the experiments of M. Pouillet, detailed in the 

 last Number of this Magazine. We can have no difficulty 

 in understanding the rationale of the action of the zinc and 

 copper surfaces in accelerating or retarding the developement 

 of the seed ; for, on the copper plate, forming the negative 



Vol. I, — No. 6. n. s. z 



