54 MASSACHUSETTS HORTICULTURAL SOCIETY. 



MEETING FOR DISCUSSION. 



Electricity and Plant-Growing. 



By L. H. Bailey, Professor of Horticulture, Cornell University, Itbaca, N. Y. 



Plants depend upon two sets of factors for their life and 

 growth : food, supplied directly by the soil and atmosphere ; 

 environmental conditions, as warmth and sunlight. Given these 

 agencies, plants thrive anywhere and at any time. There are 

 certain other circumstances, however, which greatly modify the 

 rate and direction of growth and development, without being 

 essential to the life of the plant. It is these accessory influences 

 and conditions which largely determine the value of cultivation ; 

 for amelioration is effected only when man adds some facility 

 which Nature withholds. There is no absolute or fixed standard 

 of the conditions of life, and every change in them, however 

 slight, is reflected in some way in the plant itself. Every plant is 

 different from every other plant because no two of them are 

 subjected to exactly the same conditions of existence. So it 

 happens that every condition which comes under the dominion of 

 man influences plants profoundly, because these conditions are 

 thereby widely diverted from their original scope. The difference 

 between the modification of plants in nature and in cultivation is 

 mostly one of intensity or degree, and not one of kind ; for it is 

 only when man practises direct selection that he may adopt what 

 may l)e called an unnatural or abnormal ideal. Now these 

 accessory circumstances which diversify the vegetable kingdom 

 are chiefly of four kinds : 



1. Excess in the primary conditions of life, as an unusual or 

 abnormal supply of food, warmth, or light. This, in one form or 

 another, is the chief means of the variation and consequently of 

 the evolution of i)]ants. 



2. Modifications in the periodicity of diurnal and seasonal 

 changes. Plants soon become accustomed to the circumstances in 

 which they live, or fitted into them ; and a change in this environ- 

 ment must inaugurate a new set of adaptations. What is called 

 the "rest" of cultivated plants is sim])ly an adai)tation to condi- 

 tions in which the plants once lived. In most parts of the globe 

 there is a season of enforced inactivity, due to cold or dryness ; 

 and when plants are taken from these regions into greenhouses 



