250 T)r. A. Braun on the Vegetable Individual. 



from within. This leads us from the last negative results to an 

 historical view of the attempts at a positive explanation. 



It is evident from the foregoing review that, if we would not 

 give up all hope of conceiving plants as beings, realized in indi- 

 vidual conformations, we must not allow so great and decisive an 

 importance to the external divisibility of their organism as has 

 been usually done. We must seek a decision in the essential 

 concatenation of all the steps in the plant's development forming 

 one whole, according to one idea. This is the tendency of the 

 concluding remark of Nageli, to which he is led by the relations 

 of growth and propagation in Caulerpa, when he says, that in- 

 divisibility of form is not an element essential to individuality — 

 which, indeed, must be constructed upon a new, and somewhat 

 less material basis. Link calls attention to this same unity, 

 which is expressed in the whole development of the plant, and 

 which forms the essence of its individuality, in the following true 

 words : " We cannot recognize an individual unless we are con- 

 vinced that it remains the same in different periods of its exist- 

 ence *." Nov;^ the question is just this : how can we perceive 

 such a oneness of essence amid these changes of form and mate- 

 rial ? How do we perceive that, with all its divisibility, the 

 plant remains after all really one and the same individual ? 



Every development presents a succession of phsenomena, which, 

 while they present themselves in a regular order, also show un- 

 mistakeably a point of departure, an end, and a course between 

 the two advancing after a fixed plan, and which indicate a com- 

 mon internal principle t- They point to an internal vital prin- 

 ciple J common to the whole succession ; — to a principle which 



* Link, Elem. Phil. Bot. ed. 2. p. 11. 



t Du Petit-Thouars, I. c. p. 234 : " L'indiviclu est un etre dont tovites 

 les parties sont subordonnees a un prineipe unique d'existence." Link, 

 Elem. Phil. Bot. ed. 2. p. 3 : " Nos individuum vocamus, quod ab uno 

 eodemque principio interno determinatum est, ad idealem potius quam ad 

 realem I'espicientes divisionem." 



X Spring, Ueber d. BegrifFe v. Gattung, Art u. Abart (18.38), p. 55. " It 

 is this indwelling principle which makes the individual; and in natural 

 histoi-y, every body is an individual in as far as it really exists as a single 

 being, whose existence is determined by a peculiar indwelling vital prin- 

 ciple." Spring afterwards distinguishes the systematical and the physio- 

 logical individual : in the former one phase of the development is com- 

 prehended, in the latter the whole metamorphosis. The physiological in- 

 dividual comprehends an assemblage of forms, which might be regarded by 

 a casual observer as so many systematical individuals. Still, a true system- 

 atist must protest against such a purely subjective distinction of system- 

 atical and physiological individuals. However much the embryos of 

 Mosses resemble Confervas, or the larva of an insect resembles a worm, a 

 true systematist will not separate the young individual from the developed 



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