THE SCIENCE OF GARDENING. 



61 



mistrxj. Appearing a few years ago, it 

 created no little sensation, and very possibly 

 may effect an entire revolution in the study 

 of vegetable physiology. As an analytic 

 chemist, the author ranks inferior to none ; 

 and the views he takes of the chemical pro- 

 cesses engaged in the nutrition of vegeta- 

 bles are so striking, that it becomes impera- 

 tive to direct our attention to them in the 

 course of these articles, in order to exhibit 

 truths which have not been heretofore no- 

 ticed. A few leading paragraphs will be 

 extracted, and such comments appended as 

 may be required to render more lucid the 

 admirable views of the author. 



To understand the culture of a plant, the 

 elements which constitute, or exist in its 

 structure, must be known ; therefore the 

 first part of Liebig's work is "devoted to the 

 examination of the matters which supply 

 the nutriment of plants, and of the changes 

 which these matters undergo in the living 

 organism." Subject to the operation of the 

 vital principle of a plant, which must never 

 be lost sight of, it becomes an object of the 

 greatest moment to determine what the or- 

 gans of a vegetable (that is, its tissue or 

 structure,) and the fluids they contain, are 

 composed of; for if thesehe ascertained, the 

 gardener is prepared to supply it with those 

 substances which can be converted into nu- 

 tritive aliment ; whereas, if he be ignorant 

 of these leading points, (and how many gar- 

 deners know any thing about them ?) he is 

 just as likely to poison his plants, as to pro- 

 mote their healthy development ; for " the 

 food which can serve for the production of 

 all the organs of a plant, must necessarily 

 contain all its elements." 



" The substances," says Liebig, "which 

 constitute the principal mass of every vege- 

 table, are compounds of carbon, with oxy- 

 gen and hydrogen in the proper relative 

 proportions to form water. Woody fibre. 



starch, sugar and gum, for example, are 

 such compounds of carbon with the elements 

 of water. In another class of substances 

 containing carbon as an element, oxygen 

 and hydrogen are again present, but the 

 proportion of oxygen is giealer than would 

 be required for producing water by union 

 with the hydrogen. The numerous o?ga7/2c 

 acids met with m plants, belong, with few 

 exceptions, to this class. A third class of 

 vegetable compounds contain carbon and 

 hydrogen, but vo oxygen, or less of that ele- 

 ment than would convert the hydrogen to 

 water. These may be regarded as com- 

 pounds of carbon. with the elements of wa- 

 ter and an excess of hydrogen. Such are 

 the volatile and fixed oils, Avax, and the 

 resins. Many of them have acid charac- 

 ters. The juices of all vegetables con- 

 tain organic acids, generally combined with 

 the inorganic bases or metallic oxides ; for 

 these exist in every plant, and may be de- 

 tected in its ashes. JSitiogen is an element 

 of vegetable albumen and gluten ; it is a 

 centient of the acids, and of what are term- 

 ed the ' indifferent substances ' of plants, as 

 well as of those peculiar vegetable compounds 

 which possess all the properties of metallic 

 oxides, and are known as ' organic bases.' 

 It follows, from the facts thus far detailed, 

 that the development of a plant requires the 

 presence — first, of substances containing 

 carbon and nitrogen, and capable of yield- 

 ing these elements to the growing organism. 

 Secondly of water and its elements ; and 

 lastly, of a soil to furnish the inorganic mat- 

 ters, which are likewise essential to vege- 

 table life." 



The ■'intelligent reader will at once re- 

 cognize in this quotation, the leading prin- 

 ciples of vegetable culture ; the main facts 

 are not new, nor are they doubted by any 

 philosophic observer j but they have been 

 misunda stood and misapplied, as shall be 



