268 M. Decaisne on the Root of the Madder. 



as they advance further towards the fibrous tissue, which lat- 

 ter is formed of more elongated cells arranged with equal re- 

 gularity. It is in this fibrous part that, more generally than 

 elsewhere, we find cells containing crystals as well as the ves- 

 sels of the latex ; the latter, which I have only been able to 

 detect in a single instance and by means of maceration, ap- 

 peared to me flattened, and with swellings at regular distances. 

 As regards the cellules which form the fibrous tissue, these are 

 seen to be elongated and to terminate in a blunt apex ; they 

 are transparent, and have thicker partitions than those of the 

 cellular tissue which contain the green matter, and are closely 

 applied to one another. 



The centre of the root is almost entirely formed of vessels; 

 if examined at the same stage as in the preceding observations, 

 these vessels will appear under the form of transparent elon- 

 gated cells, generally placed end to end, and forming by their 

 combination a sort of cylinder, placed in the centre of annu- 

 lated vessels which are separated by long intervals from each 

 other, and surrounded for its entire length by the cellular and 

 fibrous layers formerly described ; it extends a little further 

 and below these, forming a slight projection which constitutes 

 the spongiole. 



In this incomplete state of organization these vessels seem 

 to perform an office similar to that of the cellular tissue or 

 medulla. Later, and when they have attained their perfect 

 organization, instead of being thin and transparent, they pre- 

 sent (on examining, when highly magnified, their horizontal 

 section) many divisions, which are of a brighter or paler fawn 

 colour, and in which I could clearly distinguish the cavities 

 to which MM. De Mirbel and Hugo Mohl have lately called 

 the attention of the curious. These belong to what are termed 

 punctuated vessels, and are of uncertain diameter, with empty 

 spaces between them. These hollow spaces or intervasculary 

 meata contain a colouring matter analogous to that of the cel- 

 lular tissue ; and it is probable that the madder powder, fur- 

 nished by the central or vascular part of the root, only owes 

 its superior quality over what is obtained from the cellular 

 tissue, (or alburnum of the manufacturers,) to the entire abs- 

 ence of all foreign substances. In fact, I never observed any 



