78 PROCEEDTITGS OF THE 



bdore, " tlie coexistence of indefinite permaiioncy, und of gradual 

 or nii)id change in dift'orent races in the same area and under the 

 same pliysieal conditions " *. 



The Addresses for ISGO and 1872 are mainly devoted to geo- 

 graphical botany; and the former especially is the most masterly 

 discussion of the subject from the moderu point of view which 

 had appeared up to that date. 



I can only but briefly refer to the last of these Addresses, the 

 Report on the recent progress of Systematic Botany communicated 

 to the British Association in 187-4. In 1861 Darwin writesf: 

 " I asked Bentham to give us his ideas of species ; whether par- 

 tially with us or dead against us, he would write excellent matter." 

 And in this Keport we get the answer: — "In the limitation of 

 his orders, genera, species, &c. [the systematist] must carefully 

 observe those cases Avhere the extinctioji of races has definitely 

 isolated groups having a common parentage ; and in other 

 groups, where the preservation of intermediate forms has left 

 no such gaps, he is compelled to draw arbitrary lines of distinc- 

 tion wherever it appears to be most convenient for use. In the 

 pre-Darwinian state of the science we were taught, and I had 

 myself sti'ongly urged, that species alone had a definite existence, 

 and that genera, orders, &e. were more arbitrary, established for 

 practical use, and founded on the combination of such chnracters 

 as ajipeared the must constant in the greater number of species, 

 aud therefore the most important ; we must now test our spe- 

 cies, as well as genera or other groups, by such evidences as we 

 can collect of affinity derived from consanguinity." 



I trouble you with these extracts because on an occasion like 

 the present it appears to me of signal im[)ortauce to prove to 

 you not merely the judicial caution of Bentham, but the rarer 

 quality to find combined with it, liis mental elasticity. During 

 his scientific life Bentham saw the whole point of view of taxo- 

 nomy undergo a fundamental change. Tar from being dis- 

 mayed at the almost painful destruction of old and deeply rooted 

 beliefs, he gradually, as I have shown, reconstructed the logical 

 basis of his brancli of botanical science afresh, only to find it 

 yield a wider possibility of interest. I have dwelt at some length 

 on this topic because his period of mental transition in this im- 

 portant matter coincided, as we have seen, with his tentireof the 

 Chair of this Society. When the history of the evolutionary theory 

 comes to be written, the part which Bentham took in securing its 

 acceptance will be seen to be all the more efl'ective, because it was 

 the solid acquiescence of slowly matured conviction. 



I began by pointing out that the same inherited aptitude and con- 

 temporary influences which produced a great publicist in Jeremy 

 Bentham, yielded by an almost accidental deflection a great sys- 



* Compare Darwin's letter to Bentham, ' Life and Letters,' vol. iii. pp. 24, 25. 

 t ' Lifo and Letters,' vol. ii. p. 303. 



