of Vegetable Membrane and Fibre. 427 



it might be inferred from the author's statements that there 

 were no spiral vessels in the petals of the hyacinth ; but the 

 fact is, they are very abundant" Had I been present I might 

 at once have obviated this objection by pointing out that it 

 was founded on misapprehension, and by appealing to the 

 words of my paper, where I state, that " those spiral vessels 

 which line the interior surface of the hollow flower-stalk, 

 emerge, not into the petals, but into the pistils and stamens of 

 the flowers," from which the inference would be very different 

 from the one you suggest. 



The facts brought forward are these : The spiral vessels 

 of the root give hydrogen in excess, and the cellular tissue of 

 the root gives oxygen in excess. It is also found upon ana- 

 lysing different parts of the flower that the petals con- 

 tain an excess of oxygen, while the pistils and pollen are 

 marked by an excess of hydrogen. Hence, the question 

 arises, Is there any such connection between the root and the 

 flower as shall enable us to trace the excess of hydrogen in 

 the pistils and pollen of the flower, to the excess of hydrogen 

 in the spiral vessels of the root ? I answer that there is, for 

 it is found upon examination that those spiral vessels which 

 line the interior of the hollow flower-stalk proceed directly to 

 those parts of the flower which are marked by an excess of 

 hydrogen, emerging, not into the petals, but into the pistils 

 and stamens. And hence I wish the inference to be that those 

 spiral vessels which run within the hollow flower-stalk, and 

 contain hydrogen in excess, are a continuation of the spiral 

 vessels of the root, and that the spiral vessels of the petals and 

 leaves of the plant have their origin elsewhere. It may be 

 observed with respect to dicotyledonous plants that the latter 

 part of this conclusion would appear to be inevitable, in as 

 much as spiral vessels abound in the leaf-stalks (see Dog- 

 wood) and leaves, but "have not hitherto been seen in the 

 roots" Lindley's Introduction, p. 22. I would however take 

 this opportunity of inviting the attention of botanists to the 

 more accurate microscopic examination of the roots of dicoty- 

 ledonous plants ; for I can only conclude that spiral vessels 

 have not been seen, merely because they have not been looked 

 for. The root of the common garden mint, to instance one 

 example among others, contains spiral vessels in great abund- 

 ance. Their diameter is about ^o tn °f an mcn » I will also 

 add that the root of the wall-flower contains a very beautiful 

 and hitherto undescribed form of reticulated cellular struc- 

 ture. It is perhaps necessary to state that in consequence of 

 the great similarity between the brittle annular duct and the 

 true spiral vessel, it is impossible to speak with decision as to 



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