INTRODUCTORY 17 



a recent introduction from the east. 8 But this course of argument 

 leads to still further difficulties. For if it is true that the peculiari- 

 ties of the several species have been perfected and preserved on 

 account of their survival-value to their possessors, it follows 

 that there must be many ways of attaining the same result. 

 But since sufficient adaptation may be ensured in so many ways, 

 the disappearance of the common parent of these forms is dif- 

 ficult to understand. Obviously it must have been a plant 

 very similar in general construction to its modern representatives. 

 Like them it must have been an annual weed, with an organisation 

 conformable to that mode of life. Why then, after having been 

 duly perfected for that existence should it have been entirely 

 superseded in favour of a number of other distinct contrivances 

 for doing the same thing, and — if a gradual transition be predi- 

 cated — not only by them, but by each intermediate stage 

 between them and the original progenitor? Surely the obvious 

 inference from such facts is that the burden cast upon the theory 

 of gradual selection is far greater than it can bear; that adapta- 

 tion is not in practice a very close fit, and that the distinctions 

 between these several species of Veronica have not arisen on 

 account of their survival-value but rather because none of their 

 diversities was so damaging as to lead to the extermination of 

 its possessor. When we see these various Veronicas each rigidly 

 reproducing its parental type, all comfortably surviving in 

 competition with each other, are we not forced to the conclusion 

 that tolerance has as much to do with the diversity of species 

 as the stringency of Selection? Certainly these species owe their 

 continued existence to the fact that they are each good enough 

 to live, but how shall we refer the distinctions between them di- 

 rectly or indirectly to the determination of Natural Selection? 



8 E. Lehmann {Bull. I'Herb. Boissier, Ser. 2, VIII, 1908, p. 229) has published 

 an admirable paper on the interrelationships of these species and has instituted 

 cultural experiments which will probably much elucidate the nature of their specific 

 distinctness. As regards the existence of intermediate forms he comes to the conclu- 

 sion that two only can be so regarded. The first was described by Kuntze from 

 specimens found on a flower-pot on board a Caspian steamer, from which Leh- 

 mann proposes the new specific name Siaretensis. This comes between polita and 

 filiformis, a close ally of Tournefortii. The other, which combines some of the 

 features of both polita and Tournefortii, was found in the province of Asterabad. 

 3 



