LINN^US AND NATURAL HISTORY 129 



pair of each kind of animals was created, and that existing 

 species were the direct descendants without change of form 

 or habit from the original pair. As to their number, he said: 

 " Species tot sunt, quot )orma ab initio creates sunt" — there 

 are just so many species as there were forms created in the 

 beginning; and his oft-quoted remark, " Nulla species nova," 

 indicates in terse language his position as to the formation of 

 new species. Linnaeus took up this idea as expressing the cur- 

 rent thought, without analysis of what was involved in it. He 

 readily might have seen that if there were but a single pair 

 of each kind, some of them must have been sacrificed to 

 the hunger of the carnivorous kinds ; but, better than making 

 any theories, he might have looked for evidence in nature as 

 to the fixity of species. 



While Linnaeus first pronounced upon the fixity of species, 

 it is interesting to note that his extended observations upon 

 nature led him to see that variation among animals and plants 

 is common and extensive, and accordingly in the later editions 

 of his Systema Natures we find him receding from the position 

 that species are fixed and constant. Nevertheless, it was 

 owing to his influence, more than to that of any other writer 

 of the period, that the dogma of fixity of species was estab- 

 lished. His great contemporary Buff on looked upon species 

 as not having a fixed reality in nature, but as being fig- 

 ments of the imagination ; and we shall see in a later section 

 of this book how the idea of Linnaeus in reference to the 

 fixity of species gave way to accumulating evidence on the 

 matter. 



Summary. — The chief services of Linnaeus to natural 

 science consisted of these three things: bringing into current 

 use the binomial nomenclature, the introduction of terse 

 formulae for description, and fixing attention upon species. 

 The first two were necessary steps ; they introduced clearness 

 and order into the management of the immense number of 



