No rc'tuming 

 vessels. 



l6'2 ON THE DIFFERENT SORTS OF WOOD. 



than to collect a confused mass of uncertain details, that 



lead to no end. 



The bud ano- Du Thouars agrees with me» that each bud is only another 



gj ' kind of seed, having its cotyledons the same, and wood 



vessels reaching from the bud to the root, and ending in a 



radicle, so that each tree may be esteemed (in this respect) 



a collection of plants, really distinct from each other, 



though joined under a double cover. But in my opinion 



he carries this idea much too far in giving the same appella- 



Bui the root tion to both root and wood, for they certainly greatly difter 



and wood differ. , ■ ,_ , . . • j 



in many "^ many respects, which he seems not to nave noticed, 



respects, beside the former having a double vessel, till it joins the 



radicle, while the wood vessel is single; as I have before 

 described in my former account of this substance. He is 

 also of my opinion respecting the supposed circulation of 

 sap, which he appears persuaded does not exist, the liquor 

 flowing to the terminating branches only, to give life to 



* fresh matter, shooting from every extremity where the flow 



of jap will allow it to form ; indeed, we are now so well ac- 

 quainted with the different parts of the stem, that, if there 

 were any returning vessels, they could not (I think) but be 

 Icnown. But he is undoubtedly mistaken in saying, that 



Each leaf has each leaf has a wood vessel, as well as the bud; for, if thiS 



^roodTesseU^ was true, the stem must be as wide again. I have traced 

 this part with such exact attention, as not easily to be mis- 

 taken ; and have always found, that the set of woodjessels, 

 after meandering all over the leaf, returns on the upper side 

 of the stalk, and thus enters another leaf, that the same 

 collection may serve many hundreds. It is not difficult to 

 follow them, and is most convincing. 



Where the There is nothing that gives me more astonishment than 



the blindness of physiologists respecting the formation of the 

 flower bud. Du Thouars, as well as Mr. K., thinks it is 

 formed in the new wood, next the bark, and believes the bud 

 is generated by the sudden mixture of the wood and bark„ 

 as if they did not run side by side throughout the plant ; a 

 strange mistake! I confess it is this discovery "of the 

 filiooting of the bud'* 1 am most proud of, first because 

 it is the foundation of many important facts, that lead to 

 Consequences of no little moment ; secondly, because it is 



80 



flower bud is 



formed 



