20 MASSACHUSETTS HORTICULTURAL SOCIETY. 



vegetable, and the establishment of the plastic theory, has 

 removed the idea that there was a primordial or spontaneous 

 generation ; and these simple little lumps of albuminous combina- 

 tion of carbon are to be regarded as the natural bodies which 

 effect the transition from inorganic to organic nature. 



It is quite probable that the fruit plants which we are familiar 

 with were the lineal descendants of a class that lived before the 

 Mesozoic epoch, and a practically unlimited time must be assumed 

 for their development, and physical or geological science is unable 

 to assign any special localities for their production on account of the 

 changed condition of the earth's temperature. Of their character 

 as food products we are ignorant ; but it can be assumed that the 

 immediate descendants of the first fruits were never absolutely 

 like their parents, and that their remote posterity have differed 

 considerably from them. 



Since the distribution of fruit plant life has become a part of 

 nature, such is the order and law of creation that the mutual 

 relations of matter and motion, having been once established, have 

 ever since remained in perfect harmony and system ; and that 

 kind of life under the special conditions of climate and circum- 

 stances is exhibited that is best adapted to exist. A fruit plant 

 shows adaptation while it suffers modification ; it originates, 

 multiplies, and disappears. The favorable variation of an^^ species 

 of fruit is a slow process, relying on changes in the constitution 

 of the plant as well as those of climate and other external causes. 

 The continuance of its life depends on the development of those 

 little bodies in the seed-vessel, which are fitted by certain proces- 

 ses to unfold into new plants, which under certain conditions are 

 capable of giving origin to new races or varieties that live under 

 the sway and control of outward forces. The life of every 

 fruit plant in nature undergoes constant variation and change ; 

 the two factors always at work being a tendency to change and 

 the influence of environments. Change is the law, variation 

 proceeds if the causes are obscure, and nature encourages devia- 

 tion by progressing from the general to the special attributes of 

 the organism. The physiological function of nutrition affords a 

 general explanation of variation, which is manifested in the action 

 of water, the atmosphere, the influence of sunlight and tempera- 

 ture, of climate and soil ; while adaptation is only the consequence 

 of all those material variations produced in the change of substance 



