TRANSACTIONS 



MICROSCOPICAL SOCIETY OF LONDON. 



I. — On the Development of the Vascular Tissue of Plants, By 

 Edwin J. Quekett, F.L.S., F.B.S., &c. 



Read February 19, 1840. 



The vascular tissue of plants has frequently been the subject of in- 

 vestigation with the botanist ; but even after what has hitherto been 

 discovered and described concerning it, there remains much uncer- 

 tainty in the minds of many persons as to its true nature, and as De- 

 Candolle says, " of all parts of Vegetable Anatomy this has been the 

 most disputed, and on which persons are still less agreed." 



A study of this kind is naturally surrounded by many difficulties, 

 on account of the minuteness of the objects to which our investi- 

 gations are to be directed, and also to the delicacy of the manipula- 

 tion required to follow out the subject in the youngest parts of a 

 plant; and after attention to this subject, more or less, for several 

 years past, I venture now to give publicity to the results of my re- 

 searches. 



It has been supposed that in structure vessels differ but little from 

 cellular tissue, and that the elements of which the latter is formed are 

 only altered and converted to fulfil a different function in the former, 

 and that the development of the one will more or less correspond to 

 that of the other ; and from what has been observed, I believe this in 

 great measure to be correct, the same idea being entertained by 

 Slack in an interesting paper,* and latterly by that excellent observer 

 Schleiden, in his memoir on Phytogenesis.f 



The formation of the membranous portion of a cell has been satis- 

 factorily described by Schleiden, who details the process as commen- 



* Trans. Soc. Arts, xlix. 

 f Translated in 'Annates des Sciences Naturelles,' Seconde Serie, xi. Botaniqne. 

 TRANS. MIC. SOC. VOL. I. B 



