PRESIDENTIAL ADDRESS. 717 



partly because I wished to considei' qnestions that immediately affect lis as 

 working morphologists. 



Did time allow, we should naturally be led to recognise the same change 

 of attitude in biological science toward the problems of the origin of new 

 forms. Questions of bud-variation and mutation are clearly akin to some 

 of those considered, and the -whole subject of genetics is a special attempt 

 at a causal explanation of form and structure and the resulting functions. 

 Close co-operation between the morphological analysis of the plant and the 

 genetic analysis attained by the study of hybridisation is most desirable. It is 

 especially desirable that both should deal with structure as well as with form, 

 and in the light of individual development. 



The causal factors which have determined and guided evolution can be 

 naturally regarded as an extension of tlie same line of inquiry. The Darwinian 

 tlieory, and especially the exposition of the principle of natural selection, was 

 the greatest contribution ever made to the causal explanation of the organic 

 world. Strangely enough, it led to a period of morphological work in which 

 the causal aim was almost lost sight of. Why evolution has taken place in 

 certain directions and not in others is a problem to the solution of which causal 

 morphology will contribute. The probability of orthogenesis both in the animal 

 and vegetable kingdoms is again coming into prominence, however it is to be 

 explained. When we consider the renewed activity in this field it is well to 

 remember that, just as is the case w-ith causal morphological work, we are pick- 

 ing up a broken thread in the botanical web. Lastly, as if summing up all 

 our difficulties in one, we have the problem of adaptation. In attacking it we 

 must realise that use and purpose have often been assumed rather than proved. 

 We may look to scientific ecological work to help us to estimate the usefulness 

 or the selection value of various characters of the plant. On the other hand, 

 causal morphology may throw light on whether the ' adaptation ' has not, in some 

 cases at least, arisen before there was a ' use ' for it. The hopeful sign in the 

 recent study of these greater morphological problems is that the difficulties are 

 being more intensely realised, and that rapid solutions are justly suspect. The 

 more the causal attitude is adopted in ordinary morphological work, the more 

 hope there is of these larger questions being inductively studied rather than 

 argued about. 



The causal aim is essentially different from the historical one, but there is 

 no opposition between causal and phyletic morphology. They are rather 

 mutually helpful, for there has been an evolution not of mature plants, but of 

 specific substances exhibiting development. A deeper insight into the nature 

 of ontogeny is thus bound to be of assistance to phyletic morphology, while the 

 tested results of phyletic work afford most valuable guidance in general causal 

 morphology, though this cannot accept any limitation to single lines of descent 

 in its comparisons. 



I have tried to bring before you the possibilities of causal morphology partly 

 because the same attention has never been given to it in this country -' as to 

 other branches oi botany and partly because if morphology be conceived in this 

 broader spirit it need not be said that it has no practical bearing. I should 

 not regard it as a serious disability were the study of purely scientific interest 

 only, but this is not the case. When, if ever, we penetrate into the secrets oi 

 organisation so far as to be able to modify the organism at will (and genetics has 

 advanced in this direction), the practical possibilities become incalculable. 



Probably all of us have reflected on what changes the war may bring to 

 botanical work. It is impossible to forecast this, but I should like to emphasise 

 what my predecessor said in his Address last year as to pure science being the 

 root from which applied science must spring. Though results may seem far 

 off, we must not slacken, but redouble our efforts towards the solution of the 

 fundamental problems of the organism. This can be done without any 

 antagonism between pure and applied botany ; indeed, there is every advantage 



"' One of the few exceptions to this is the excellent semi-popular lecture 

 delivered to this section at Southport by Professor Farmer. (' On Stimulus and 

 Mechanism as Factors in Organisation,' JVew P/iyfoIogist, vol. ii. p. 193.) Also 

 Address to Section K at the Leicester Meeting (1907). 



