22 HATCH EXPERIMENT STATION. [Jan. 



The results of electrical treatment of various kinds and of 

 different strengths of currents, in which 3,446 treated radish 

 plants were compared with 2,022 normal or untreated ones, 

 are shown in the summary. These comparisons are based 

 on the growth of the normal plants with which the treated 

 were grown, and not on the total normals, since the duration 

 of experiments in one table does not correspond with those 

 in another ; or, in other words, there existed some difference 

 in the degree of maturity of the various crops. This method 

 of comparison is necessary, since the treatment varied in 

 time, and the experiments in each table were not parallel 

 throughout. The results show, however, a})})reciable gains ; 

 and, as they are averages, the percentages represent more 

 accurately the influence of electrical treatment, the total gain 

 for roots and tops being 27.34 per cent. A notable feature 

 is seen in acceleration of tops, which showed about two and 

 a half times more growth than that shown by the roots. In 

 the case of the two interrupted induced-current experiments 

 the reverse holds true, there being more than twice as much 

 growth of roots as tops. This current exerts a different 

 physiological effect on plants than the direct current. 



Experiments with Lettuce. 

 The tendency of electrical stimuli to accelerate the growth 

 of the toi)S of radish plants more than the roots suggested 

 the idea of substituting lettuce. Lettuce possesses a differ- 

 ent and more desirable habit of growth, it would seem, for 

 electrical stimulation. The variety of lettuce grown in all 

 cases Avas that known as the Boston head type, so conmionly 

 used by market gardeners in Massachusetts. The plants 

 were grown according to the customary manner of growing 

 lettuce ; namely, the seed was sown in a small box of soil. 

 When the seedlings were an inch or two high they were 

 transplanted into larger boxes containing loam ; and when 

 they had formed tliree or four leaves two or three inches 

 long, they were carefully selected, as regards vigor and size, 

 and transi)lanted into the experimental boxes, as in the radish 

 expeiiments. The; loam in which they were started was of 

 uniform (|uality and similar texture to that used in the boxes. 

 Twenty-four plants were set in each box, which allowed room 



