160 Lindlej/s Theory of Horticulture, 



is the only difference between the two systems. But there is 

 another, still closer, analogy between them. If you have a close 

 boiler and elbow turns at the extremity of your pipes, there will 

 be little or no sediment. Just so with a tree or branch. If you 

 pull off the leaves as they are produced, the circulation keeps on 

 as before ; but you will have no formation of wood, buds, &c., 

 for want of the proper sediment.* 



The young reader must now turn to Dr. Lindley's way of ex- 

 plaining the circulation, and he will find the subject increasing in 

 interest at every succeeding paragraph. Dr. Lindley is evidently 

 at home here, and will be sure to detain you till he makes you 

 understand the whole of this beautiful process, and every little 

 thing about it which is likely to be of any use to you ; if you 

 never heard how flowers are formed, this part of the subject will 

 be apt to electrify you. You will be astonished, too, to find how 

 easy it is to learn all this yourself, and you will also wonder 

 how he could find out all this ; but these great botanists are aU 

 ways prying into the secrets of plants, and they have glasses 

 that would make a little twig as big as a gate post. By these 

 means they see things that you or I would never think of looking 

 after. 



I must now leave you with the doctor, while I see how he 

 and the gardeners agree about hybridising. Here the angry critic 

 might ask where and when was the theory of vegetable super- 

 foetation " proved by the most satisfactory course of enquiry ? " 

 It was first believed in by Mr. Knight; at least he wrote a paper 

 on it in one of the early volumes of the Traiisnctioiis of the Hort, 

 Soc. The subject of his experiments was the garden pea ; an 

 excellent plant as far as the safety of the experiments is con- 

 cerned, but an indifferent one to draw conclusions from : had it 

 not been for the shape of its flowers, guarding the style and 

 stigma from the intrusion of foreign pollen, it would be as diffi- 

 cult to preserve its varieties true as those of the turnip. It is 

 not in the nature of things that an original writer like Mr. 

 Knight should be always right in his conclusions. I cannot say 

 this part of his views is impossible to be proved ; but I can safely 

 say it is the next degree to it. I was smitten with this doctrine 

 once, and, after a great many fruitless experiments for the last 



* " A growing shoot, although divested of its leaves as soon as they are un- 

 folded, will grow as fast, and increase as much in diameter, as another shoot 

 with its leaves in full operation, other circumstances being the same; but, if 

 you continue disleafing the second season, there will hardly be any addition 

 to the diameter of the shoot. Disbudding in this manner the summer's shoots, 

 as they proceed in growth, is the simplest mode I know of for reducing the 

 strength of an over-luxuriant tree. As little or none of the sap taken up by 

 such shoots is elaborated, it is entirely lost to the general secretion of the 

 parent tree. By this method I have, in three years, reduced healthy vigorous 

 young pear trees to the point of starvation," {Gard. Mag. for 1837, p. 203.) 



