258 MR. S. LE M. MOORE'S STUDIES 



have to deal with. u pure cellulose," if indeed there be such a 

 substance. 



Let us now take the Fig. The chief point to notice here is 

 the complete difference between its xylem and its hard bast in 

 respect of their reactions, for whereas the xylem closely resembles 

 that of the Rose, and may be supposed to contain an iron- 

 greening tannin in its walls, the hard bast of the Hose is quite 

 different from that of the Fig. Assuming the foregoing reac- 

 tions in the latter tissue to be due to one substance, this is 

 an iron-greening body, giving other tannin reactions, behaving 

 negatively to proteid tests, except (X) faintly, taking a lavender 

 colour (as does tannic acid) with copper sulphate, a pinkish red 

 with iodine, with Schulze's solution a rose colour, a blue with 

 methyl-green, and a sky-blue with picric-blue, and behaving 

 like the tannins in its refusal to take up carmine. All this is 

 evidence as to the existence in these walls of a tannin or tannin- 

 like body ; and the fact that the same reactions are yielded by 

 the latex as by (a) the xylem, and by (b) the hard bast, is of 

 some value as a confirmation of this view, since latex is well 

 known as being rich in tannin. Moreover, when we come to 

 study tannin in the tissues of the Fig, we get all the various 

 reactions characteristic of the xylem and of the hard bast respec- 

 tively : the latter are yielded chiefly by the short clavate hairs 

 with which the young parts (stems, leaves, coenanthia) are abun- 

 dantly clothed, but also by certain epidermal cells as well. On 

 the other hand, the tannin of the xylem can be found in the 

 epiderm and in the long hairs clothing young parts. The 

 extra-xylemic tissues other than the hard bast appear to have in 

 their walls the same substance as is found in the hard bast, but 

 in very slight, often only just appreciable, quantity. 

 • The other cases are simpler ; in the meristem w r alls of Isoetes 

 lacustris, and in thelignified elements of Arundo Phragmites and 

 the Maize, there is evidence of an iron-greening tannin reacting 

 like catechu. The purple reaction of the bast and unlignified 

 xylem-walls of the Maize may perhaps indicate the existence of 

 cellulose in a pure state ; but although the reaction ,is always 

 supposed to point to cellulose, the matter is one worth further 

 examination. In these cases no opportunity has offered or 

 studying tannin in the tissues. 



