546 
PROFESSOR H. MARSHALL WARD OX THE 
noticed before and is figured by Frank, and is also a character of the mycelium found 
in Juncus bufonius, and named by Weber* Entorrhiza. In suitable preparations 
the hypha may be seen to swell up inside the substance of the cell-wall, and it looks 
as if the widening was due to the cellulose wall itself (fig. 14). Two possibilities 
suggest themselves : the swelling might be due to increased nutrition—a less probable 
view ; or, as I think more probably, the cellulose wall extends by the growth of the 
cell after the hypha has pierced it, carrying the insertion of the hypha with it as 
its area increases. As the tubercle becomes older the hyphse in the cortex of the 
root turn yellowish and gradually decompose, so that no trace of them can be 
detected in the larger tubercles which have broken through the cortex of the root. 
In the cells of the very young tubercle the finer branches of the above hypha can 
be seen behaving similarly as regards their passage through the walls and across 
the lumina ; and, although they become too fine to enable the observer to decide as 
to the presence or absence of a cell-wall and septa, it may no doubt be assumed that 
the characters are essentially the same. It is often possible to see the hyphse 
running in the substance of the cell-wall (figs. 9 and 9 a). In one respect these 
more ultimate hyphse differ, however; they send out branches which end blindly in 
the cavities of the cells (figs. 15-18). These branches may be simple, or they 
may have several rounded or tufted bodies projecting from them, and looking like 
haustoria. The surface of these haustorium-like projections is often found presenting 
the appearance shown in figs. 16 and 17. Numerous very minute protuberances 
stand off from the rest of the mass. 
In very thin fresh sections of tubercles, about the size of a mustard-seed or smaller, 
and which are only just beginning to project markedly from the root, the projections 
just referred to are very numerous, and every cell of the inner meristematic mass of 
the tubercle seems to be provided with the branches bearing them. A change is also 
noted in the cell-contents in these cases. In place of the normal-looking protoplasm 
of the cells in the earlier stages, the protoplasm now becomes extremely vacuolated 
and frothy, and the tiny bacterium-1 ike coi’puscles referred to are found to be 
gradually increasing in number in the cells (fig. 12). At a slightly later stage these 
bacterium-like corpuscles have become distributed in dense crowds throughout the 
frothing mass of protoplasm, and they become so numerous that they obscure the 
hyphse, and the appearance is that of a plasmodium, gradually becoming more and 
more densely filled with granules. At length, the enlarged cell is seen to contain a 
dense mass of the granules arranged around a large central vacuole (figs. 12 and 4). 
The nucleus remains in the protoplasm. So dense is the mass of granules in the 
protoplasm at last, and so sharply defined the vacuole, that extremely thin prepara¬ 
tions hardened in osmic acid or picric acid, and then in absolute alcohol, can be 
washed and stained with hsematoxylin and mounted in Canada balsam in the usual 
way, without destroying this arrangement (fig. 4). 
* ‘ Bofcan. Zeitung,’ 1884 (No. 24). 
