By Thomas Andrew Knight, Esq. 119 



ends of the cuttings upon the bottom of the pots, in the 

 manner recommended in the concise, but valuable, paper of 

 Mr. Hawkins, in the Horticultural Transactions of 1813 * 

 might have been productive of good effects, though the 

 cause of the beneficial influence of such pressure is not very 

 obvious. It cannot, I think, be owing to the more ready 

 absorption of moisture by the earth of the pot, for those 

 employed by me were composed of a very compact brick 

 earth, which scarcely at all absorbed moisture; and the 

 pressure of cuttings against the side of the pots, did not 

 afford, by any means, the same result ; and it is still less 

 probable that any good effects could arise from the stagna- 

 tion of the water in the bottom of the pots. I am therefore 

 rather disposed to attribute the ready emission of roots, by 

 Mr. Luscombe's Orange, and my Mulberry cuttings, in some 

 measure, to the mechanical action of the hard and smooth 

 surface of the bottom of the pots ; for external mechanical 

 causes have a much more extensive influence upon the 

 actions of plants than is usually imagined, of which I could 

 cite many examples. When a cutting has been placed in 

 contact with soft and yielding mould only, and has lived a 

 short time without emitting roots, and subsequently perished, 

 a large mass of mal-organized cellular bark is generally 

 found to have accumulated on its lower extremity. When 

 on the contrary, the end of the cutting is firmly held down 

 upon the bottom of the pot by the mould which surrounds, 

 and is attached to it, the protrusion of this fungous sub- 

 stance is prevented, and a new direction given to the de- 

 scending organizable fluid of the plant, which theoretical 



* See page 1 2. 



