( cxxvii ) 



towards and ultimately lead to exclusive selectiou for survival 

 or extinction. When Nature intervenes it is indeed often, 

 perhaps generally, with a sentence of death — sometimes, as 

 applied to the extinction of a species, a lingering one — but 

 with a very large number of conspicuous characters she does 

 not appear to intervene at all, thus leaving very considerable 

 parts of the organic life we see around us as spheres in which 

 natural selection does not for the time being practically 

 operate. May I put it in this way 1 — that there is selection 

 between competing classes of variation, those which are of the 

 greatest biological importance, often not conspicuous ones, or, 

 it may be, altogether hidden from our observation, coming to 

 the front. Just as, if I may be pardoned for an illustration 

 drawn from familiar human history — we all belong to the 

 Animal Kingdom — it was rivalry between courtly and social 

 qualities which led to and maintained eminence in France 

 under the Monarchy, but all this ceased to operate during the 

 grim struggles of the great revolution there. 



Hah its. 



But without discussing this question any further I proceed 

 now to call attention to a set of characters which have no 

 place in merely diagnostic works, and often receive scant 

 mention in descriptive works of larger scope — as characters 

 which may possibly explain, in some cases in which this 

 suggested tolerance cannot be invoked, why some of the 

 conspicuous differences I have dwelt on may be of practical 

 unimportance. The set of characters to which I would thus 

 di-aw attention is that which may be summed up for the 

 present in the word "habits." In the habits of a species, 

 taking the word in a wide and comprehensive sense, we may 

 sometimes find a uniformity missing in its facies, and possibly 

 important enough to enable a species possessing these habits 

 to find and hold a place for itself, with all its diversely- 

 coloured forms; the habits, or the internal qualities they 

 connote, being perhaps the important attribute possessed by 

 them all, and binding all together in a common situation. 



Before proceeding further let me acknowledge my deep 

 indebtedness to Professor Meldola's Presidential Address to 

 this Society in 1896. A part of what follows is nothing more 



