628 Summary View of the Progress of' Gardeiimg, 



potatoes, it will be observed in the latter article, may be preserved 

 for a number of years, and yet retain their nutritive properties. 

 One of the most valuable papers on practical horticulture in the 

 present volume is one by Mr. Drummond, quoted from the Hor- 

 ticultural Transactions, " On the Cultivation of Pears, and the 

 Management of Fruit Borders " (p. 402.). It is full of instruc- 

 tion, and ought to be maturely studied by the young gardener. 



Agriculture and Dom,estic Economy, including Bee Culture^ 

 will be found to have received their customary share of attention 

 as secondary objects ; but we consider it unnecessary to do more 

 than refer to the Table of Contents, more especially to our 

 Miscellaneous Intelligence. 



Gardeji Literature. — A great many books have been reviewed 

 or noticed in the present volume, of which three are of peculiar 

 value : De Candolle's Vegetable Organography (p. 163.), Liebig's 

 Organic Chemistry, in its Application to Agricidture and Physio- 

 logy, and Dr. Lindley's Theory of Horticidture. The last book 

 ought to be in the possession of every gardener, and the others 

 in the hands of all who can afford to procure them. Pro- 

 fessor Liebig's work is the most valuable of the kind which 

 has been published since the days of Sir Humphry Davy. It 

 has generally been supposed that the chief source of nutriment 

 to plants depends on the presence in soils of a substance to which 

 the name of humus has been given, and which is extracted or 

 absorbed by them during the process of vegetation ; this notion 

 of the absorption of a solid substance by plants has hitherto 

 prevailed among physiologists who have considered the subject ; 

 and in the 6th edition of Sir H. Davy's Agricidtural Chemistry, 

 it is stated that " vegetable and animal substances deposited in 

 the soil, as is shown by universal experience, are consumed dur- 

 ing vegetation, and they can only nourish the plant by affording 

 solid matters capable of being dissolved by X'oater, or gaseous sub- 

 stances capable of being absorbed by the fluids in the leaves of 

 vegetables ; but such parts of them as are rendered gaseous, and 

 that pass into the atmosphere, must produce a comparatively 

 small effect ; for gases soon become diffused through the mass of 

 the surrounding air. The great object in the application of 

 manure should be to make it afford as much soluble matter as 

 possible to the roots of the plant, and that in a slow and gradual 

 manner, so that it may be entirely consumed in forming its sap and 

 organised parts." Professor Liebig dissents from this opinion, and 

 adduces the most complete evidence that humus, in its pure form, 

 or as it exists in the soil, does not yield the smallest nourishment 

 to plants, in consequence of the low soluble power of this sub- 

 stance, either alone or in combination. He therefore concludes 

 that the carbon must be derived from other sources, chiefly, 

 though not entirely, from the atmosphere, by the decomposition 



