814 THE ORIGIN OF FLORAL STRUCTURES. 



therefore, the survival of the fittest, as first issuing from " Constitu- 

 tional Selection." It must be borne in mind that Darwin himself 

 towards the close of his life seemed distinctly to move in the 

 direction of these criticisms, and, with the absolute justice and 

 candour which always distinguished him, readily admitted that he 

 had in his earlier works stated too strongly the case for " cross- 

 fertilisation" and "Natural Selection." Followers of the great 

 naturalist will not need to be reminded that a rejection of some of 

 his theories is quite compatible with intense admiration for his life 

 and labours in the cause of science. 



But the present work is by no means merely negative and 

 destructive of previously accepted opinions. It gives a novel 

 theory, which ig, to say the least, most intelligible, suggestive, and 

 capable of explaining very many of the phenomena of floral struc- 

 ture. This new theory ought to be specially welcome to evolu- 

 tionists, since it relieves them from a difficulty which has always 

 been felt as to the reason of variation. To say that the seedlings 

 of a particular plant vary from their parent, because they have a 

 tendency to variation, is a most unsatisfactory and evasive explana- 

 tion, indeed simply amounts to saying " they vary because they 

 vary." Those who have read (who has not ? ) the delightful « Life 

 and Letters of Charles Darwin,' will remember his characteristic 

 reply, when acknowledging the justice of one of Huxley's criticisms 

 on the Origin of Species :— « If, as I must think, external condi- 

 tions produce little direct effect, what the devil determines each 

 particular variation ? What makes a tuft of feathers come on a 



5J™, B ^ ad ' or moss on a moss-rose ? There is < Much virtue in 

 1J. Prof. Henslow cuts, instead of untying, this Grordian knot, 

 internal conditions, he tells us, do produce great effect, and are, in 

 truth, the direct cause of variation. He looks lovingly towards 

 that " new Lamarckism " which was frowned upon by the President 

 ot the Biological Section at the recent meeting of the British 

 Association : he goes back to the " Monde ambiant " of Geoffroy 

 ot. Jlilaire, the surrounding circumstances and conditions of 



• A, 1 ? ? ^° rd ' the " eu vironment." His formula for variation 

 is tnat it is the result of the " responsive power of protoplasm 

 to external stimuli;" an d he finds the stimulating agency, as 



+ i -■ ■ <? ~ "wwuomcB is inai insects, iiavmg ue 



t he juicy tissues of flowers, by perpetually withdraw! 

 thereby kept up a flow of the secretion which has 



iar as flowers are concerned, to be chiefly that of insects. For 

 example, with regard to secretive tissues he tells us, "The 



fu ?l° r W ln of paries is that insects, having been attracted to 



awing fluids, have 



Vi i~, r v - u " c Dcusuuu yyxxxv.x x lt .o become here- 



uitary, while the irritated spot has developed into a glandular 

 secreting organ." Irregularity or " zygomorphism " is ascribed to 

 a change wrought by generations of insects on originally regular 

 wnoris. livery one has noticed how in many Orchids*, Labiate, 

 ana papilionaceous Leguminosa, the flower seems as if specially 

 constructed so as to afford a secure landing-place for insects. Such 

 structures are explained as the resultant of various forces brought 

 to bear upon the flower by « the weight of the insect in front, the 

 local irritations behind, due to the thrust of the insect's head and 



