M. Decaisne on the Root of the Madder. 269 



crystals among the vessels, and this is the only difference I 

 have been able to detect between the parts of the two tissues 

 containing the colouring principle. However, the woody 

 part, completely stripped of the surrounding cellular tissues, 

 affords the very finest powders, according to the observations 

 of the manufacturers in the South of France ; these remarks 

 contradicting those of M. E. Koechlin, as will be shortly seen. 

 I ought to state that I have cut through these vessels at dif- 

 ferent periods of growth, and never found them filled with li- 

 quid. It is they which appear, in an early stage, to produce 

 the radicles; in fact, when examining young roots, I have often 

 seen, after removing the cellular tissue by maceration, that the 

 ligneous body formed of the vessels I have described, has 

 emitted from its circumference projections more or less appa- 

 rent, which afterwards by elongation produce the radicles 

 which are already noticed. 



If the root be again scrutinized when far more advanced, 

 still its internal structure will appear to have undergone no 

 material change, and the organization which I have described 

 is found to be the same ; the only appreciable difference con- 

 sisting in a proportionate increase of the tissues, whose several 

 layers are thickened by the addition of new rows. 



The madder root, which was pale yellow at the earliest period 

 of its developing, gradually acquires a deeper and deeper tinge, 

 as takes place in age with the several parts of almost all ve- 

 getables. The same phasnomenon exists in the cotyledons ; for 

 if a section of the infant stalk be made at the period when it 

 first bursts from the seed, the cotyledons will be seen to emit 

 a yellowish fluid, which shortly assumes a decidedly red hue. 



By the above facts, it may be ascertained that, so far as de- 

 pends on the arrangement of the different parts, the root of 

 madder departs in no respect from the common structure of 

 roots. No peculiar cavities, designated by the name of reser- 

 voirs for the proper juices, seem to exist. If the fluid which 

 the vessels of the latex contain were in any respect unlike that 

 which is observable in all the cells, it can be only in the fainter 

 colour, since these are with difficulty discerned ; and as to the 

 existence of crystals in some of the cells, this is by no means 



