54< General and scientific Knowledge important to Gardeners. 



To reconcile these discrepancies, a greater generalising power 

 must be put in operation. A gardener would then see that a 

 process which succeeded well under his management would not 

 answer equally well under that of his neighbour, unless all cir- 

 cumstances were alike. Hence the superiority which one scien- 

 tific principle of action possesses over a load of mere practical 

 directions. In the former case, operations are regulated accord- 

 ing to circumstances and situation ; in the latter, operations are 

 performed in every circumstance alike. Thus, too, a knowledge 

 of the sciences upon which the first principles of gardening are 

 founded would lead to greater unanimity upon points which are 

 now subjects of dispute. The questions respecting what a plant 

 is ; what are its modes of accretion ; does the sap descend ? is 

 there a circulation of fluids ? is the sap organisable ? is it capa- 

 ble of expanding, under the direction of the vital principle, what 

 the plant contained in embryo ? or does all accretion proceed 

 from the expansion of a rudimental membrane, named the vital 

 envelope, as contended for by one of the most experienced 

 physiologists of the day ? are questions which will be satisfactorily 

 solved only when we become better acquainted with the diversi- 

 fied structure and habits of the vegetable world. What the 

 food of plants is ; how that food can be most economically and 

 plentifully supplied ; what are the uses of leaves ; whether are 

 they digestive, respirative, or excretory organs, or all united; 

 how to know the fitness of a soil for certain crops ; the mecha- 

 nical operations most suitable ; the kind of manure most appro- 

 priate; the state in which that manure ought to be, whether 

 fresh, partly or wholly decomposed ; will only be known when 

 we possess a greater acquaintance with chemical principles, and 

 the nature of the crops we wish to raise. Whether the system 

 of forcing generally adopted, of keeping nearly a uniform tem- 

 perature by day and by night, or one more in unison with nature, 

 be followed, will depend not so much upon the result, as upon 

 the knowledge of the influence of heat, when not acting in unison 

 with the decomposing agency of light. Not to be tedious, we 

 may refer to the insect tribes by which we are assailed, and ask if 

 there is much likelihood that, with all our many recipes, we shall 

 be able to put a stop to the ravages of the turnip fly, the devas- 

 tations of the thrips, and the molestation of many others, if no 

 one acquainted with the science of entomology will bring his 

 investigations to bear upon the subject? 



Some of the sciences above referred to, for instance, ento- 

 mology, we confess we have little or no knowledge of; but we 

 refer to it, as well as to others, in support of our general propo- 

 sition, and in the hope that some may be induced to give it, as 

 well as others, a share of their attention. Were we all to study 

 with equal ardour the same departments of knowledge, we 



