PHAN 7 EROGAMIA : FOLIAR ORGANS. 275 



examples, being in fact nothing else than the stipules of an abortive 

 principal leaf. 



Finally, the same influence to which the parts closely crowded 

 in the bud are subject, may merely cause the un symmetrical deve- 

 lopment of the two halves a particular foliar organ, so that one 

 side, or that part of the leaf lying on one side of the mid-nerve, 

 assumes a form different from that of the other half, of which the 

 species of Begonia afford a striking example. 



The processes of development sketched here are the only ones in the life 

 of the plant to which the words "growing together" or "abortion" can be 

 applied, if we would confine ourselves within the boundaries of a circum- 

 spect, scientific activity. " Growing together " only has a meaning when 

 I apply it to the union of two originally actually distinct parts, in con- 

 sequence of a process of growth ; "abortion" only when I understand by 

 it the arrested development and destruction of a part already actually 

 existing in a rudimentary condition. Nothing, certainly, has confused 

 or led botanists more from their point than the misuse of these two 

 words. That many take it to be much easier to build fancies about a 

 phenomenon according to an arbitrarily chosen type, and to settle the 

 question by a word thus tin-own in. than to be compelled to see, after 

 weeks and months of painful investigation, that their so beautifully 

 imagined type is nothing, I readily believe ; but must nevertheless assert 

 that in the latter alone lies genuine scientific activity, while the former 

 are toys of such who neither do nor wish to understand that the aim of 

 our endeavours in Natural Science, is a theory of the actual and not of 

 our imaginations. The misuse also depends altogether upon an empi- 

 rical and methodical faultiness, upon an empirical, in so far that we are 

 yet wholly without the facts on which to establish scientifically a law of 

 the position of leaves for Phanerogamic plants in general, as for the 

 individual groups, while abortion and growing together can, in any case, 

 only be used for the explanation of exceptions to a well-grounded law ; 

 upon a methodical, since an observed regularity may indeed serve in 

 many cases to make us remark upon the possibility of a natural law 

 lying at the bottom of it, but still is not the law itself, the actual exist- 

 ence, much more the decision, of which is then first to be sought for and 

 established.* Here we have the misuse of the comparative method, 

 on which I have before animadverted. If we find five leaves in a definite 

 position in definite order in a series of plants, and in another plant, allied in 

 many respects to the former, only four, comparison will of course lead 

 us to guess that one leaf is abortive here, and call upon us to investigate; but 

 it is this very investigation alone which can decide as to actual abortion. 

 Any other mode of inquiry is as impossible as it would be unscientific. The 

 individual case would have to be excluded if, in mathematical development 

 from constituent metaphysical principles, we could deduce a law accord- 

 ing to which exactly five leaves must stand in this position, where then 

 the necessity conditioned by an exceptionless mathematically definite 

 law would suffice to establish the decision ; " for this appearance a leaf 

 must have been obliterated here." We have no such laws at all in our 



* See, on this head, the excellent elucidations of Fries, Versuch einer Kritik der 

 Principien der \Vahrscheinlichkeitsrechnung, Brunswick, 1842. 



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