HARDWICKE'S SCIENCE-GOSSIP. 



: 3i 



the week, to the aggregate amount of o - o6 of an inch. 

 The duration of registered bright sunshine in the 

 week was 42 '4 hours, against 547 hours at Glynde 

 Place, Lewes. 



In October the isotherms form deep curves as they 

 cross England and Scotland. The isotherm of 48 

 passes through Lanark, Roxburgh, and Haddington ; 

 that of 49 through Wigtown, Kirkcudbright, Stock- 

 town and Newcastle ; of 50 through Liverpool, 

 Derby and Hull ; of 51 through Denbigh, Hereford, 

 Reading, Hertford and Cambridge, to the Wash ; of 

 52 through Anglesea, Swansea, Salisbury, London, 

 and the east coast off Ipswich ; of 53 through 

 Haverford West, Devonport, Brighton, and Canter- 

 bury. These isotherms represent the mean average 

 temperature of the places named for the month. 



The average rainfall in October is 2 inches on the 

 east coast, 3 inches on the south coast, and 4 inches 

 on the greater part of the west coast. 



THE RED LEAF AGAIN : A REPLY. 

 By G. W. Bulman, M.A. 



I HOPE Mr. Tansley will forgive me when I say 

 that I cannot find anything in his paper 

 (Science-Gossip, June, 18S8) which at all weakens 

 any of the arguments drawn by me from a red leaf, 

 and from my observation of the habits of bees 

 (Science-Gossip, October, 1887). 



In fact, I find in it admissions and quotations from 

 the authorities which fully confirm my general 

 proposition, viz. that red and blue flowers are not 

 developed by the selective action of bees. 



In the paper referred to, I drew two conclusions 

 from the red leaf : 



(1.) That a brilliant red might be developed in a 

 plant without the selective action of insects. 



(2.) That bees were not attracted merely by a red 

 colour in a plant. 



With regard to the first, I do not wish to 

 exaggerate its importance in connection with what I 

 will call for shortness the bee-selection theory : it 

 does not prove the theory impossible, but it does 

 show that it is not necessary. If a brilliant red leaf 

 can be otherwise produced, why not a flower ? And 

 it is believed by the advocates of the theory in 

 question that coloured petals were originally green 

 leaves. 



As Sir John Lubbock expresses it : "I believe 

 .... that all blue flowers have descended from 

 ancestors in which the flowers were green ; or, to 

 speak more precisely, in which the leaves immediately 

 surrounding the stamens and pistil were green." 

 ("Ants, Bees, and Wasps," p. 308.) 



As to Mr. Tansley's quotation from Dr. Sorby, I 

 cannot understand how it is supposed fully to meet my 

 objection. It is simply a statement that the colouring 

 matter in the petals of flowers is often the same as in 



the leaves, and that in " many crimson, pink, and 

 red flowers," the development of colour " seems as if 

 related to extra oxidation." 



Looking at the red leaf, I say, "If this final result 

 can be arrived at without selection, why not the red 

 petal ? " Surely the fact, that the colour is in both 

 cases due to the same chemical changes, does not 

 make the suggestion less probable. 



And Mr. Tansley's own conclusions are that the 

 development of coloured pigments in flowers and 

 leaves is due to the same primary causes, but that 

 the colours of the former are "stereotyped and 

 perpetuated by insect selection." This is an admis- 

 sion of the conclusion to which my own arguments 

 tended, viz., that colour in flowers is not developed 

 by the selective action of insects. I suggested, that, 

 since it could be fully developed in a leaf without 

 insect agency, it might be so also in a flower : Mr. 

 Tansley says, that "clearly" it is so. 



I am aware that the development of colour by 

 chemical action spoken of by Dr. Sorby does not 

 exclude the idea of development by insect selection : 

 it has nothing whatever to do with it. In any case 

 whether insects have influenced the development or 

 not, the colour is necessarily due to chemical 

 changes. But the connection in which Mr. Tansley 

 uses the word " development " seems to imply that 

 the coloration of the flower was as completely 

 effected as that of the leaf before insect selection 

 come into play to stereotype and perpetuate it. 



With regard to the "stereotyping " of the developed 

 colours by insect selection, it is conceivable that this 

 might occur if insects showed that critical appreciation 

 of the colours of flowers with which some people 

 credit them. I will return to this point when I come 

 to my argument from the habits of bees with regard 

 to different coloured flowers. In my former paper, 

 however, I said nothing against this "stereotyping" 

 theory. I was not even aware of its existence : my 

 arguments were rather against such views as those 

 expressed by Mr. Grant Allen in — for example — his 

 paper on " Monk's-hood " (" Knowledge," September 

 29th, 1S82). Speaking of the blue colour of 

 monk's-hood, he says : 



"Next, we may suppose, the large green sepals, 

 being much exposed to view, began to acquire a 

 bluish tinge, as all the upper parts of highly developed 

 plants are apt to do ; and the bluer they became, the 

 more conspicuous they looked, and therefore the 

 better they got on in competition with their neigh- 

 bours, especially since bees are particularly fond of 

 blue." 



This is the sort of process I understand when I 

 speak of the development of colour by the selective 

 action of insects : it seems to me more in accordance 

 with Darwinism than Mr. Tansley's theory, which 

 seems to admit that the colour may be fully developed 

 without insect selection, and is only stereotyped 

 and perpetuated by the same. 



