174 Miscellaneous Facts and Obseriiations. 



In support of this opinion, Dr. Darwin has addu- 

 ced several very ingenious arguments, for the full ex- 

 position of which I must refer to his Phytologia^, a 

 work replete with learning, and marked, in every 

 page, with the genius of the British Lucretius. 

 It must be confessed, however, that much of mere 

 hypothesis is attached to Darwin's observations, con- 

 cerning the uses of the parts of vegetables. He has 

 too frequently assumed as points completely esta- 

 blished, points that are still involved in great uncer- 

 tainty. Thus, a fundamental part of this author's 

 reasoning concerning the use of the corolla is the as- 

 sumption of the fact, that in this part of the fructifi- 

 cation, there is a two-fold system of vessels, corres- 

 ponding to the pulmonary artery and veins of animals. 

 Now, many experiments, which I have made, com- 

 pel me to entertain some doubts relative to the exist- 

 ence of an arterial and venal system in the corolla. 

 What I have already said concerning the leavesf, 

 may, with equal propriety, be extended to the corolla. 

 I have often succeeded in colouring this part of the 

 plant, with the juice of the Phytolacca, and other co- 

 louring matters: but I have not been able to convince 

 myself, that the colouring matter is exclusively car- 

 ried, in the first instance, along the upper surface of 

 the corolla; and I never could decidedly perceive, 

 that it was returned by a venous system, on the under 

 side of the petals. I do not mean, however, to deny 



• Sect. IV. 



t Elements of Botany, &tc. Part I. pages 57—59. 



