14 HATCH EXPERIMENT STATION. [Jan. 



of acceleration (see Fig. 1). That plants respond to elec- 

 trical stimuli in various ways is well known. The efiect, 

 however, which electricity has upon the growth of plants has 

 not been well understood, and the results obtained by vari- 

 ous experiments have not been convincing, for reasons ah'eady 

 pointed out. The fact has been definitely established that 



M R MX 



-I 1 1 h 



A CCELERATION -RETARDATION- "DEATH- 



FiG. 1. — Diagram sliowing range of electric current affecting plants. 

 M, minimum; O, optimum, or current producing greatest stimulus; 

 MX, maximum, or death current; R to MX, retardation current. 



electrical currents exist in the soil, and also in the plant; in 

 fact, wherever chemical activity occurs electric currents are 

 likely to be present, although these currents may be com- 

 paratively insignificant, and require delicate instruments for 

 their detection. 



The following experiments in stimulating plants with elec- 

 tricity have been carried on in this department for some 

 years, and previous to undertaking this work man}^ thou- 

 sands of plants have been experimented ^vith, and the mini- 

 mum, optimum and maximum currents have been established 

 by us in a general way. AVe therefore had more or less a 

 definite idea in mind as to what strength of current we 

 wished to apply at the beginning of our work. The experi- 

 ments we are about to describe, therefore, represent only a 

 small part of those which Ave have made, and these were 

 made under conditions resembling those employed for com- 

 mercial purposes. We shall, however, interpret the results 

 of these experiments in the light of those obtained from our 

 long study given to the subject, rather than from what these 

 particular tables show. 



The work was carried on in the greenhouse, during the 

 summer months. The plants utilized were radishes and let- 

 tuce, which were selected for special reasons as being suitable 

 for our work. The plants were grown in wooden boxes, 53 

 inches long, 32 inches Avide and 7 inches deep. These boxes 

 were placed on movable trucks, or in sonu; cases on supports 

 18 inches from the floor. In all cases they were insulated. 

 The soil employed was of a uniform <|uality and texture, and 



