Cc. A. BARBER. 29 
by the crushed cells of the host. The whole mass is probably 
filled with ferment formed in the haustorial cells, and, while 
the remains of haustorial cells are added on the one side, 
those of the host may sometimes also be seen on the other, 
and the mass thus assumes a considerable thickness (Plate 
X, fig. 2, b). Long after the secreting cells have lost their 
activity, it would thus be possible for the yellow mass to continue 
its action on the host’s tissues, until the latter are effectively 
protected by the formation ofa layer of cork. Sooner or later 
various pigments are added to the mass and it assumes colours 
characteristic of different hosts. All stages from clear yellow 
(Citrus), through reds and browns (Acacics and Albizzias) are 
met with, until, in suh plantsas Diospyros and Strychnos, 
the colour becomes an inky black. 
It is interesting to note that this coloured separating 
substance is always wanting opposite to the rows of vessels 
in the sucker (Plate X, figs. 1 and 4), a fact tending to show 
that absorption no longer takes place where the yellow sub- 
stance is formed. A study of fig. 2 on Plate XI leads to the 
same conclusion. In staining for starch, the tissues of host and 
haustorium were coloured blue wherever the dark secretion 
layer separated them (st). In other places no coloration was 
observed. It is obvious that no active flow of nutriment 
takes place where the cells are full of starch. 
EFFECT ON THE Hosvt’s TISSUES. 
19. The general effect of the haustorial action on the 
host’s tissues 1s, similar in Cansjera to that in Santalum and 
Olax, but the sucker is smaller, and this seems to cause certain 
differences. 
The wings of the host’s bark are uniformly attacked, as 
we have seen, by the active sides of the sucker. The attacked 
parts are generally cut off by a layer of cork from the living cells 
of the host’s root. The wings are, however, small, probably 
on account of the poor development of the sucker, And this 
