THE TRUE THEOllY QF GRAFTS. 



with laths likewise coated with moss. If for a lonp^ sea-voyapre, care should l)e 

 takrii to close the box, some holes Ijciiiir made in the top, to prevent the shoots 

 beeoniinc: mouldy. This is excellent advice. 



Dr. Lindley adds, that so lonj; as it was believed that absolute wood was formed 

 corporeally from above downwards, it was inferred that the lower parts of a ])lant 

 must be gradually encased in solid matter derived from branches, and that, consc- 

 (piently, of necessity, the stock of a plant must be enveloped in layer above layer 

 of the scion. It is needless to repeat tlic arguments employed in sup])ort of this 

 view; they were cogent, and, for a long time, held to be irrefragable. The appli- 

 cation of the theory to grafting, led, among other things, to the conclusion, that 

 a scion would speedily form a sheath of wood over the stock, and thus secure 

 itself forever. Once to form a good union, was therefore looked upon as suflicient 

 security for the permanent life of the grafted jtlant. Cases, ajiparently at variance 

 with the theory, occurred now and then, but plausible explanations of such instances 

 were readily found. 



It is, however, now certain, continues the Doctor, that although wood is formed 

 by a descending process, yet that its descent is not in an organized state. Fluid 

 matter, out of which it is produced, passes, indeed, from aljove downwards, but 

 the formation itself is wholly local and superficial, and, 

 consequently, there is no such thing as an encasement of 

 the lower part of a tree by wood descending from above. 

 That important fact having been once established, the 

 union of a scion and its stock evidently becomes a case of 

 mere adhesion, extremely powerful in some cases, feeble 

 and readily destroyed in others. There are, therefore, 

 two essentially different results obtained by grafting — the 

 one permanent, the other transitory. The accomjjanying 

 example affords a new demonstration that the union between 

 a scion and its stock is no other than that now described. 

 About the beginning of Sei)tember, 1853, Dr. Maclean, 

 of Colchester, an ingenious experimentalist and good 

 physiologist, grafted a young ])lant of the White Silesian 

 Beet upon a root of Red Beet, and vice versa. At the 

 time of the experiment, the plants were each about as thick 

 as a straw. A com])Iete junction Avas effected, and when, 

 in 1854, the White Beet grafted on Red was taken out of 

 the ground, its longitudinal section exhibited the appear- 

 ance represented in the figure. There was a slight con- 

 traction at the line of junction ; al)ove the line of contrac- 

 tion, the plant was absolutely white, below it was absolutely 

 red. Not a trace of blending of the two colors could be 

 discovered. By similar experiments on other vegetables 

 and plants. Dr. Maclean had so far assured himself of the 

 perfect independence of scion and stock as to acquire the 

 belief that neither the coloring nor any of the si)ecific cha- 

 racters of the one or the other, would or could be altered 

 ,' by their union. The result of the trial wholly confirmed 



'^ ' ' "^ that view, and demonstrated that the White Beet adhered 



to the R.ed Beet by mere junction of cellular matter, that 

 of the scion and stock holding together in the first instance, and each afterwards 

 roducing its own coloring matter in its own new cells, as they formed su 

 ally, the red cells adhering to the white cells while in the -nascent state 



