SPECIES AS TO VARIATION, ETC. 195 



means which have been adduced to explain the origin of the 

 species by ' natural selection,' or a process of variation from 

 external influences, are inadequate to account for the phenom- 

 ena. The law of phyllotaxis, which governs the evolution of 

 leaves around the axis of a plant, is as nearly constant in its 

 manifestation as any of the physical laws connected with the 

 material world. Each instance, however different from an- 

 other, can be shown to b9 a term of some series of continued 

 fractions. When this is coupled with the geometrical law gov- 

 erning the evolution of form, so manifest in some departments 

 of the animal kingdom, e. g., the spiral shells of the Mollusca, 

 it is difficult to believe that there is not, in Nature, a deeper- 

 seated and innate principle, to the operation of which natural 

 selection is merely an adjunct. The whole range of the Mam- 

 malia, fossil and recent, cannot furnish a species which has had 

 a wider geographical distribution, and passed through a longer 

 term of time, and through more extreme changes of climatal 

 conditions, than the mammoth. If species are so unstable, and 

 so susceptible of mutation through such influences, why does 

 that extinct form stand out so signally a monument of stability? 

 By his admirable researches and earnest writings, Darwin has, 

 beyond all his contemporaries, given an impulse to the philo- 

 sophical investigation of the most backward and obscure branch 

 of the biological sciences of his day ; he has laid the founda- 

 tions of a great edifice ; but he need not be surprised if, in the 

 progress of erection, the superstructure is altered by his success- 

 ors, like the Duomo of MUan from the Roman to a different 

 style of architecture." 



Entertaining ourselves the opinion that something 

 more than natural selection is requisite to account for 

 the orderly production and succession of species, we 

 offer two incidental remarks upon the above extract. 



1. TVe find in it — in the phrase "natural selec- 

 tion, or a process of variation from external influ- 

 ences " — an example of the very common confusion 

 of two distinct things, viz., variation and natural 



