314 BEY. G. HE27SLOW OX THE ABSORPTION OF EAItf 



(Mars 1878) ; and while our conclusions are identical, our re- 

 spective experiments really supplement each other ; so that al- 

 though his results have now been published, it is thought advi- 

 sable to publish a selection of mine also as corroborating those of 

 M. Boussingault. 



Hales, in 1731, and Bonnet, in 1753, alike inferred, but did not 

 actually prove, that plants absorbed rain and dew. 



De Candolle, Meyen, and Treviranus and others, however, ob- 

 jected to Bonnet's conclusions, asserting positively, but appa- 

 rently without experimental evidence in support, that the leaves 

 which he laid on the surface of water kept fresh for lengthened 

 periods solely because transpiration was assumed to be arrested. 

 Had they fixed watch-glasses on the surfaces of the leaves, as I 

 have done, transpiration would have been easily detected. 



Notwithstanding these objectors, a general belief seems to have 

 "been held until 1857, when M. Duchartre performed his experi- 

 ments ; and although he had himself been previously of the opinion 

 that if plants could not absorb vapour (which Boussingault has 

 now proved to be the case) they could at least imbibe dew and 

 rain, yet he was led to abandon this view ; and he is responsible 

 for the opposite one being generally held till now by vegetable 

 physiologists. It should be observed that practical horticulturists 

 have never abandoned the idea that plants can and do absorb 

 water by their leaves. 



As this change of view has been somewhat of an obstruction to 

 the progress of vegetable physiology, and, as far as I am aware, no 

 serious attempt has been made to refute M. Duchartre's con- 

 clusions, I do not think it out of place to try and expose their 

 fallacy. 



He commences* his paper by objecting strongly to experimen- 

 ters using cut leaves or shoots instead of growing plants in their 

 entirety ; but he gives no grounds for raising this objection. On 

 the other hand, it is easy to prove that all the functions of a leal 

 are carried on when detached as when growing : transpiration can 

 be readily detected ; and M. Garreau found in his experiments 

 on respiration that " detached leaves gave the same results as 

 those which remained attached to the plant" f; and if a green shoot 



* " Recherches sur les rapports des plantes avec la Rosee," Bull, cle la Soc. x>ot. 

 de France, t. iy. p. 940; " Recherches experiment a les sur les rapports des plantes 

 avec la rosee et les brouillards," Ann. des Sc. Nat. 4me ser. xv. p. 109. 



t " De la respiration chez les plantes," Ann. des Sc. 3me ser. xv. p. 12 (1851)- 



