258 CONTRIBUTIONS TO 



success. My researches also with respect to this newly -arising 

 formative layer between bark and wood are by no means 

 concluded. 



Before, however, I proceed to communicate my observations 

 on this subject, it is necessary once more to take up the ques- 

 tion of the individuality of plants. I have already remarked 

 above that, in the strictest sense of the word, only the separate 

 cell deserves to be called an individual. If we go a step 

 farther, we might define each axis with its lateral organs to be 

 individual beings. If, however, we disregard this circumstance 

 of the plant being composed of cells and similar axes, and con- 

 ceive the term individual, as applied to the organic world, to 

 signify a body which cannot be divided into two or more simi- 

 lar ones without the abolition of its idea of totality, and whose 

 vital process has a fixed point of commencement and termi- 

 nation in definite periodicity, it thence follows that the her- 

 baceous (planta annua) and the true biennial plants, which 

 flower in the second year, and then die off entirely, are the only 

 ones which can be regarded as individuals in the vegetable 

 kingdom. The idea of individual life also necessarily requires 

 as a characteristic that individual death should be a condition 

 of the organization itself. But where such a death does not 

 take place as a final termination from internal necessity, as an 

 internal preconditioned cessation of the organizing force, there 

 also must individuality be out of the question* This is the 

 case, however, only in the above-mentioned plants, and from 

 them solely, therefore, as from the prototype, must we set out, 

 in all researches into the nature and life of the vegetable 

 organism. 



In order to facilitate the transition to what is to follow, I will 

 now proceed to the exposition of the two different modes of 

 propagation. It either takes place by a process which has 

 hitherto been called impregnation in plants, and to which a 

 sexual difference has been ascribed (Wiegmann's Archiv, 1837, 

 vol. i, p. 290, &c), or by division ; the plant, for instance, deve- 

 loping on itself a perfectly similar individual, and then at an 

 appointed time dismissing it. This latter, the formation of so- 

 called bulbilli, &c. occurs, together with the former, in only a 

 small number of plants. We must, however, make ourselves 

 somewhat more intimately acquainted with it. This formation, 



