CHAPTER XVI 



effect of electricity on growth 

 § 1. Effect op Electeicity upon" the Rate op Geowth 



Electeical changes are so intimately associated with chem- 

 ical changes that we may reasonably expect not only to find that 

 the metabolic processes of growth are accompanied by the 

 development of electricity, but also to find that an electric 

 current disturbs growth. It is indeed known that electricity 

 is produced in seedlings, for jMullee-Hettlingen" ('83) has 

 obtained from a seedling of Vicia faba by connecting the two 

 extremities a maximum electro- 

 motive force of about one-tenth 

 of a volt. (Fig. 114.) There is 

 thus in the living plant an elec- 

 tric stress. Will an outside cur- 

 rent, which must affect that of the 

 organism, disturb also its growth? 



In the case of the growing 

 animal even a slight current of 

 electricity is usually injurious. 

 Thus LoMBAEDiNi ('68) and 

 WiNDLE ('93 and '95) have sub- 

 jected the Qgg of the chick to 

 such a current running trans- 

 versely through the embryo, with 

 the result that the embryo either 

 soon ceased to develop or devel- 

 oped abnormally. RirscONi ('40), 



on the other hand, believed that a slight current accelerated 

 the development of the frog's egg. More extended experiments 

 with known strengths of currents are much to be desired.* 



Fig. 114. — Vicia seedling. The lines 

 uniting different points of the seed- 

 ling may represent the wires run- 

 ning to the galvanometer ; the points 

 themselves are those from, which 

 the current was led off ; the arrows 

 go with the currents in the wires. 



(From MiJLLEE-HETTLINGEX, '83.) 



* Certain unconfirmed results with a powerful magnet deserve to be noted. 

 Maggiokini ('84) found that developing hens' eggs subjected to this agent pro- 

 duced four times the normal number of cases of arrested development. 



405 



