■LIZ THE HISTORY OF BIOLOGY 



that the Linnasan reform was from the beginning more adapted to vegetables 

 than to animals. 



The conception of species: their immutability 

 But, all the same, Linnjeus's contribution to the development of biology 

 has been of vital importance to science as a whole. In the first place, by fixing 

 the term ' ' species " as he did, he laid the foundation for the system of classi- 

 fication as it exists today. At the time when the dispute on the descent theory 

 was raging at its hottest, Linnasus, it is true, was exposed to the severest 

 censure just because he had declared the species to be immutable, as they 

 were created from the beginning — the dispute, in fact, raged just as much 

 over the belief in the creation as over the constancy of the species itself — 

 but in spite of the fact that the immutability theory is now abandoned, 

 the Linnasan species is used in practice by systematic science even today, 

 because it has not been possible to find any better substitute for it; a species 

 is regarded as the sum total of those individuals which resemble one another 

 as if they had a common origin. The other systematical categories which 

 Linnasus created also remain to this day, although some new ones have come 

 into existence as well. And quite as remarkable is Linnasus's influence on 

 what may be called the technical side of the classification system, which 

 he himself actually founded, exactly as it is applied today : his rules regarding 

 nomenclature, description, characterization, and synonymy have really 

 proved so complete that in principle posterity has had but little to add to 

 them. Moreover, the whole of this radical reform was carried out at one 

 stroke by a hitherto unknown young man after only a few short years of 

 utterly inadequate scientific training. This wonderful result was rendered 

 possible only by the fact that Linnasus combined exceptionally well-trained 

 powers of observation with an unparalleled natural genius for the formal 

 side of science. This latter gift was, so to speak, in his very blood: he had 

 a passion for classifying everything that came within his grasp; his medical 

 writings consist of groups of diseases in tabular form; his predecessors in 

 science he likewise classified under various headings, and once he even ar- 

 ranged, mostly as a joke, all his contemporary botanists according to mili- 

 tary rank, with himself as their general. For the fact that this mania for 

 classification never degenerated into mere dull pedantry he had to thank 

 his extraordinary love of nature and his passion and gift for observing life 

 in all its manifestations. It was this quality that prevented him from stag- 

 nating at the point to which he had so rapidly attained, instead of which 

 he spent his whole life striving to extend and perfect the science that he had 

 already so thoroughly recreated. These efforts, which, with the aid of his 

 pupils, he continued as long as his powers lasted, consisted in improving 

 the system he had already created, extending and perfecting the natural 

 vegetable system that he had already made it his ambition to work out, 



