ORGANI CDEVELOPEMENT. 93 



which, when adult, similar shoots proceed. Compare this with the 

 strawberry and its creeper, which, in like manner, after growing 

 to a certain length, developes a bud of leaves, the plant-individual, 

 again to send out other creepers, and form, at intervals, other 

 leaves. Here we see that the bud acquires a certain length before 

 it is finally perfected ; the line of cellules, with which the forming 

 bud begun, was gradually acquiring the requisite elaborations, and 

 concentration within, to develope the new individual. And after 

 the distance is reached, the process is still gradual in both cases. 

 The polyp rises first as a small protuberance, which gradually 

 lengthens into its tubular cylindrical base, and finally the polyp- 

 flower is formed at apex. Very similar, as is well known, is the fact 

 with the strawberry.* 



91. The production of a branch in zoophytes, at a single budding 

 process ( 70), is another of those singular facts, which appear to find 

 their analogies rather among vegetables than animals ; and we see it 

 exhibited on a large scale in the thyrse of lilac blossoms. The 

 general principles of the process are shown in the figures of the 

 Alga, on page 91. The budding cellules, from b to m, if viewed 

 as separated from the coralline, form together a similarly ramose 

 branch : and if, instead of each cellule, there were elongated series, 

 and the whole, with accompanying tissues and fibres, formed a 

 prominent ramose branch, instead of being embedded, as in the 

 coralline, we should have a clump of flowers like the lilac blossom: 

 or, if still partly embedded, the cluster would resemble that of the 

 Alcyonium. This subdivision of the flower stems in the lilac, 

 takes place at nearly regular intervals, and these intervals decrease 

 towards the flowers, as in the cellules of the Alga. The process 

 appears to be similar, except, that instead of one cellule, we have a 

 series of them before subdivision, precisely as we have a series in the 



* There is little doubt that were the cases equally well brought out to view in all the 

 steps, we should find as much reason to say that the ovarian lamellae of the polyp are 

 altered tentacles, as that the seed-vessels and petals of a flower are altered leaves. The 

 same kind of cellules, under different circumstances, originate both. Excessive nourish- 

 ment is known to cause the production of leaf-buds in place of flowers, and also to make 

 a petal from a stamen ; and for the reason, as has been explained, that the latter, in each 

 instance, differs from the other only in requiring, for the production of its few peculiar cha- 

 racters, a slower and more quiet and concentrated action of the forces at work, while the 

 former may result from a less delicate process of vital chemistry. Only under circumstances 

 in the utmost degree favourable, will certain chemical compositions take place, and here, 

 in like manner, for the difference is in the resulting combinations, the forces must be 

 nicely balanced and not of too rapid application. 



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