782 

 Proceedings of Societies, S^c. 



Botanical Society of Edinburgh, 



Thursdmj, November 11, 1852. {Seventeenth Session). — Dr. Sel- 

 ler, President, in the chair. 



Various donations were announced to the Society's library and 

 herbarium, and also to the Museum of Economic Botany at the Royal 

 Botanic Garden. 



The following papers were read : — 



Tubular Structure in Plants. 



* On the Development of Tubular Structure in Plants ;' by R. Hob- 

 son, M.D., Cantab., Leeds. Communicated by Dr. Balfour. 



The object of this paper was to show the mode in which tubular 

 structure is formed by the aggregation of cells in a linear series, and 

 the subsequent absorption of thp partition walls. The structure 

 selected for observation was the moniliform hair found on the claw of 

 the spurred petal of the heart's-ease {Viola tricolor). The author 

 stated that " If the structure of the tube is traced, under the micro- 

 scope, from the root, or base, upwards, the lower part will be found 

 fully formed (tubular), having gradually substituted a tubular for its 

 previously cellular formation. A little higher up, absorption of the 

 partition walls (the united portion of the cells) is yet incomplete, being 

 in transitu from cell into tube ; whilst the remaining part is entirely 

 cellular to the extreme point, which point is, in fact, a simple cell. 



" There may be distinctly seen, in a portion of this multicellular 

 tube, near to its base, marks sufficient to prove that those points of 

 the cells which have been primarily in union to form the tube have 

 now been absorbed, or in some other way removed, and that this ab- 

 sorption, or removal, has taken place precisely in an equal degree 

 from the centre of the different septa, or united portions of the cells, 

 towards the periphery of the tube, to the extent required to perfect 

 Nature's ' handiwork.' The marks to which I allude are triflingly 

 apparent annular contractions." 



The author also made some observations as to the time occupied in 

 the formation of the tubes. He remarked : — 



" In order to ascertain whether the mutation of cell into tube occu- 

 pied much time, I instituted a comparison between the tubular ))or- 

 tion of the hair on the full-blown flower, and that on the flower just 



