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 
further, we might define each axis with its lateral organs to be 
individual beings. If, however, we disregard this circumstance 
of the plant bemg 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 imdividual, 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, 
