Food qfPlantSi a?id on training Fruit Trees. 437 



Art. V. On the Food of Plants, and on training Fruit Trees. 

 By Joseph Hayward, Esq., Author of " The Science of Hor- 

 ticulture," " The Science of Agriculture," and other Works. 



Sir, 



In my last (Vol. V. p. 394.) I endeavoured to call the atten- 

 tion of your readers to the important object of establishing the 

 practice of gardening on the tried principles of science. It is 

 evident that clear definitions are the fountains of science ; and 

 to show that nothing can be more opposed to the establish- 

 ment of science than the incongruous use of undefinable terms, 

 we need only refer to the confusion occasioned by the use of 

 the term manure. To avoid this, in my first essay on the food 

 of plants, I explained the means by which chemists had come 

 to the conclusion, that the pabulum or nutritive principle 

 does not necessarily form a part of the earth, but is a sub- 

 stance which may be abstracted from it, or imparted to it, by 

 the agency of the vegetable and animal part of the world ; 

 and which substance is called carbon: and, as it is known 

 that without some other active principle in nature carbon 

 is often inert, I explained the objections which led me to 

 conclude that alkaline salts, or their bases, form the active 

 principle. I will now, with your leave, explain some other 

 conclusions which I have come to, from the observations I 

 have made on the effects of the quantity and quality of food 

 consumed by plants. 



From the little that has been understood of the science, 

 many of the most common terms used in horticulture are vague 

 and uncertain, and the terminology is altogether inadequate 

 to the explanation of our ideas. We are therefore obliged 

 to resort to analogies, and to the use of those terms that in a 

 strict sense may be applicable to animals only : thus, when 

 speaking of the food of animals, we mean solids, as we know 

 that they require drink besides ; and, as plants cannot take 

 any thing into their bodies but liquids, the term food may 

 appear inapplicable, yet by no other familiar term can we 

 convey an idea of the substance by which the nutritive prin- 

 ciple is to be conveyed. It may be said that the food of 

 animals cannot be nutritive until digested in the stomach ; and 

 that plants have not stomachs for the reception or digestion 

 of solids. True ; but as plants are stationary, and compelled 

 to receive their food through the agency of the earth, we may 

 consider the earth as performing the office of the stomach 

 for plants. As the food of plants, from whatever substances 

 derived, must be reduced to a soluble state, and duly blended 

 and diluted with water ; and as the reduction and preparation 



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