REPRODUCTION OF PLANTS. 535 



Botany as Surgery does to Zoology. On the union of two individuals, 

 however, through eyes, grafts, or inarching, I have a few words to say. 

 Independent of the care which should be taken in this operation to 

 bring in contact living cell-tissue and, as much as possible, similar tissue, 

 as wood with wood, alburnum with alburnum, cambium with cambium, 

 and to avoid the access of air, yet the success of this operation entirely 

 depends on the species of plants which are thus united. The rule is, 

 that the nearer plants stand to each other, as the varieties of a genus, 

 the more certain will be the result. Plants belonging to different natural 

 families will not unite. The exceptions are only apparent. A twig 

 will blossom and form leaves in water or moist sand, and so it will 

 in the moist tissue of another plant ; but it will not grow together with 

 the other, unless the chemical processes in both plants are similar. Did 

 we know the specific peculiarities of the chemical processes in all plants, 

 then we might a priori determine the results of such transference, and 

 need not to perform the experiment. So soon as the union is effected, 

 the nature of the future-formed cells and organs depends principally on 

 the nature of the new individual, that is to say, when it is the only 

 growing portion on the stock. Yet the stock must always exert a greater 

 or less influence on the eye or graft, as the sap brought to it must pass 

 through the cells of the stock, and become changed there. In this case 

 the relations are too complicated to enable us to offer an explanation. All 

 that is known on the subject is detailed in manuals of horticulture. I will 

 mention one case. If a branch of a quick-growing plant is grafted upon 

 a very slow-growing one, as, for instance, the branch of a plum upon a 

 sloe-stock, the graft will grow rapidly, but not so the stock, which retains 

 its slow-growing character*, a striking example of the permanency of 

 the specific life of the stock, and, as it appears to me, affording a fatal argu- 

 ment against the pretended descent of the sap. If a descending bark- 

 sap existed, the sloe-stock would be naturally covered with annual rings 

 of plum-wood from the graft, and it would grow in proportion to the 

 growth of the graft ; but this is by no means the case, for the new 

 annual rings are formed, not out of a descending bark-sap, but out of a 

 cell development of the cambium already existing in the stock, and 

 Laving essentially the same characters. The formation of new wood 

 of the nature of the graft has always been taken for granted, in 

 order to prove the descent of the bark- sap ; but we find that this wood 

 does not partake of the nature of the graft, and that it must therefore be 

 formed independently of any descending juices. 



209. Peculiar relations are exhibited sometimes in the capacity 

 of plants for regular reproduction. Every simple plant, in the 

 most stringent sense of the word, is only capable of propagation 

 once ; with the unfolding of its terminal bud into reproductive 

 organs, its life is closed. But even the greatest part of the simple 

 plants, in a wide sense, whose axillary buds are exclusively de- 

 veloped into flowers, are only once capable of reproduction ; the 

 plant is so exhausted through the reproductive effort, that it dies. 

 This is the case with annual and biennial plants (plantce monocar- 

 picce). Sometimes they continue to live, and the terminal bud 



* Lindk-y: A theory of Horticulture, p. 237. 



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