CHAP, in.] the Dogma of Constancy of Species. 1 1 1 



be assigned. Where Linnaeus had spoken of a class-plant or 

 generic plant, the expression ' plan of symmetry ' or ' type ' was 

 used, meaning an ideal original form, from which numerous 

 related forms might be derived. It was left undecided, whether 

 this ideal form ever really existed, or whether it was merely the 

 result of intellectual abstraction; and thus the forms of thought 

 of the old philosophy soon began to reappear. The Platonic 

 ideas, though mere abstractions and therefore only products of 

 the understanding, had been regarded not only by the school 

 of Plato, but also by the so-called Realists among the school- 

 men, as really existing things. The systematists obtained the 

 idea of a type by abstraction, and the next step was easy, to 

 ascribe with the Platonists an objective existence to this crea- 

 ture of thought, and to conceive of the type in the sense of a 

 Platonic idea. This was the only view that was possible in 

 combination with the dogma of the constancy of species, and 

 so Elias Fries, in his 'Corpus Florarum,' 1835, in speaking of 

 the natural system, could consistently say, ' est quoddam supra- 

 natural e,' and maintain that each division of it 'ideam quandam 

 exponit.' So long as the constancy of species is maintained, 

 there is no escaping from the conclusion drawn by Fries, but 

 it is equally certain that systematic botany at the same time 

 ceases to be a scientific account of nature. Systematists, 

 adopting this conclusion as necessarily following from the 

 dogma, might consider themselves as seeking to express in the 

 natural system the plan of creation, the thought of the Creator 

 himself; but in this way systematic botany became mixed up 

 with theological notions, and it is easy to understand why the 

 first feeble attempts at a theory of descent encountered such 

 obstinate, nay, fanatical opposition from professed systematists, 

 who looked upon the system as something above nature, a 

 component part of their religion. And if we look back we 

 find that these views are based on the dogma of the constancy 

 of species, while Linnaeus' ' Philosophia Botanica ' teaches us 

 on what grounds this dogma rests, where it says, ' Novas species 



