60 mr. s. le m, moore's studies 



I also boiled sections of the rhizome of Arunclo Fhragmites in 

 pure hydrochloric acid for a couple of minutes. By this treat- 

 ment the lignified walls were turned straw-yellow, and on trying 

 Millon's reaction, after thoroughly washing away all traces of 

 acid, a much browner colour than usual was taken by the lignified 

 walls. Something similar is seen when hydrochloric acid is 

 added to a solution of catechu ; the solution takes a yellow 

 colour, becoming deeper on boiling, and on pouring in Millon's 

 fluid a dirty white precipitate is thrown down, and this does not 

 change colour on boiling. 





Two reactions of lignified cell-walls have a significant bearin 

 upon "Wiesner's theory : these are their refusal to take up 

 aniline-blue and carmine, two distinctively proteid tests, and 

 when we remember that tannin will not stain with either of 

 these dyes, we have in this a strong confirmation of the theory 

 here advocated. It may indeed be retorted upon me that in 

 the memoirs on callus I have myself described a substance 

 (paracallus) which, although an undoubted proteid, yet will 

 take up neither aniline-blue nor carmine. But it must not 

 be forgotten that, whereas paracallus is a very dense sub- 

 stance, and apparently derives its inability to stain from this 

 fact, lignified cell-walls are specially adapted to take up fluids, 

 and so should stain well were protein present in them — indeed, 

 they stain admirably with dyes which are also taken up by iron- 

 greening tannin. But these are only two of a large series of 

 reactions which cannot all be merely accidental, and this has 

 firmly convinced me that the substance in these cell-walls is not 

 protein. 



A solution of catechu contains mimo-tannic acid and catechin : 

 both these substances are said to give a green precipitate with 

 iron salts, and I much regret not having been able to get them 

 in the pure state. If the reactions of catechin are like those of 



pyrocatechin, the substance in cell-walls would seem to be mimo- 

 tannic acid, for a solution of pyrocatechin reacts quite differently 

 from the substance in cell- walls. This matter, however, requires 

 further study. 



I have asked, what is protein doing in the cell-wall ? The 

 rejoinder to this might be, what is the glucoside doing there ? 

 In answer to this, reference might be made to the suggestion 

 thrown out in my memoir on tannin that the glucoside, an other- 

 wise useless bodv, is made use of in lignification. But in view or 



