Retrospective Criticism. 711 



Gardeners seem to be aware of this ; as I have known them, when they 

 desired a particularly heavy fruit, such as a melon, a pine, &c., about which 

 they desired to make a boast, keep the plant in a close moist atmosphere, 

 and shade it from bright sunshine; knowing that, by admitting a current of 

 air and the full glare of sunshine, the watery juices of the fruit would be 

 perspired, and a chemical change sooner produced upon its substances; 

 and that, consequently, though it would ripen sooner, be better-coloured, 

 and much better-flavoured, yet it would be diminished in its weight. I do 

 not mention these things for the purpose of undervaluing light and air; I 

 am quite convinced of their extreme importance; but, at the same time, I 

 believe that this importance does not, in general, consist so much in giving 

 food to the plant, as in acting, along with heat,as a stimulant of the vital prin- 

 ciple, and in changing the nature of and assimilating the substances which the 

 plant has already absorbed, and rendering them fit for its nourishment and 

 support, in a manner something similar to the changes that are produced 

 upon our food by the organs of digestion, and upon our blood by its 

 passage through the lungs. That plants, when exposed to too much light, 

 die from over-excitement, is true; but I am not yet convinced of the pro- 

 priety of saying that it is from their " feeding too fast." It is occasioned 

 by too great perspiration, and by a too rapid decomposition of the carbonic 

 acid which is contained in the plant, and, consequently, too great an expul- 

 sion of oxygen ; but I should hardly think from too great an absorption of 

 carbon fi-om the atmosphere, as the appearance of the leaves would indi- 

 cate that they had very little of that power remaining. The gardener who 

 has observed the change eifected by removing a tender plant from partial 

 shade into bright sunshine will judge for himself. 



The Opinions of Air. Gorrie and Mr. Elles on transplanting Trees and 

 striking Cuttings. — "I may have said too much upon the exhaling properties of 

 plants ; but it seems necessary, because the overlooking of this circum- 

 stance has led to much difference of opinion. As an evidence, I might 

 refer to the sentiments of Mr. Gorrie and Mr. Elles respecting the ma- 

 nagement of transplanted trees. I mention these gentlemen with the 

 greatest deference, as they are both a high honour to the profession. 

 Mr. Gorrie (Vol. VI. p. 44.) advocates the thinning out of the top of a 

 transplanted tree, to make it proportionable to the roots ; Mr. Elles (in the 

 same volume, p. 546.) says " touch not a twig nor a leaf." Both allude 

 to the practice of striking cuttings, in support of their opinions. Mr. Gorrie 

 takes off a i'e'N of the leaves, as an excess of foliage exhausts the sap in 

 the shoot; Mr. Elles and N. H. (Vol. VI. p. 413.) are convinced of the 

 impropriety of taking off a single leaf. Now, whose opinion am I to follow ? 

 None of them, I reply, before examining the subject for myself. Let us 

 attend to the process of striking cuttmgs, as illustrative of the principle 

 involved in the management of transplanted trees. We leave the top of 

 the tree exposed to heat, light, and air. Do we thus act towards our 

 cuttings ? No. Is not the first thing we attend to the preventing of per- 

 spiration and the expulsion of oxygen, by keeping them from the full in- 

 fluence of the sun and air, by artificial shading, and covering them with a 

 frame, or a hand or a bell glass ? The number of leaves is of relative im- 

 portance ; the fewer that are left, the less will be the exhaling or per- 

 spiring surface; the greater their number, the greater may be the success, 

 but that success will wholly depend upon the greater care bestowec! in 

 preventing evaporation from the leaves, enabling them to inhale the greatest 

 quantity of ox3'gen, and to exhale the least, by a slow decomposition 

 of their carbonic acid gas. We do not expose them to sun and air before 

 they have obtained roots ; and when we pot them off, we again shade them 

 a little before the roots are established in their new quarters. Mr. Elles 

 speaks of the absurdity of taking off a leaf of a celery plant, &c., when 



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