1870— 1SS2] DE CANDOLLE 369 



read your remarks on Smilax, whenever I receive the essay ' Letter 2S0 

 which you kindly say that you will send me. There is much 

 justice in your criticisms 2 on my use of the terms object, 

 end, purpose ; but those who believe that organs have been 

 gradually modified for Natural Selection for a special pur- 

 pose may, 1 think, use the above terms correctly, though 

 no conscious being has intervened. I have found much 

 difficulty in my occasional attempts to avoid these terms, 

 but I might perhaps have always spoken of a beneficial 

 or serviceable effect. My son Francis will be interested by 

 hearing about Smilax. He has dispatched to you a copy of 

 his paper on the glands of Dipsaais? and I hope that you will 

 find time to read it, for the case seems to me a new and 

 highly remarkable one. We are now hard at work on an 

 attempt to make out the function or use of the bloom or 

 waxy secretion on the leaves and fruit of many plants ; but 

 I doubt greatly whether our experiments will tell us much. 4 

 If you have any decided opinion whether plants with con- 

 spicuously glaucous leaves are more frequent in hot than in 

 temperate or cold, in dry than in damp countries, I should 

 be grateful if you would add to your many kindnesses by 

 informing me. Pray give my kind remembrances to your 

 son, and tell him that my son has been trying on a large 

 scale the effects of feeding Droscra with meat, and the results 

 are most striking and far more favourable than I anticipated. 



1 Monographic Phanerogamarum, Vol. I. In his treatment of the 

 Smilacere, De Candolle distinguishes : — Heterosmilax which has dioecious 

 flowers without a trace of aborted stamens or pistils, Smilax with sterile 

 stamens in the female flowers, and Rhipogonum with hermaphrodite flowers. 



2 The passage criticised by De Candolle is in Forms of Flowers (p. 7) : 

 " It is a natural inference that their corollas have been increased in size 

 for this special purpose." De Candolle goes on to give an account of 

 the " recherche linguistique" which, with characteristic fairness, he under- 

 took to ascertain whether the word "purpose" differs in meaning from 

 the corresponding French word " but." 



3 Quart. Journ. Mic. Sri., 1877. 



4 " As it is we have made out clearly that with some plants (chiefly 

 succulent) the bloom checks evaporation — with some certainly prevents 

 attacks of insects ; with some sea-shore plants prevents injury from salt- 

 water, and, I believe, with a few prevents injury from pure water resting 

 on the leaves." (See letter to Sir W. Thiselton-Dyer, Life and Let Lis, 

 III., p. 341. A paper on the same subject by Francis Darwin was pub- 

 lished in ihefoum. Linn. Soc. XXII.) 



24 



