40 
F. O BOWER. 
ment between those of figs. 1 and 2, is represented in fig. 3. 1 
Among the normal cells of the limiting tissue, which appear 
thin walled and full of granular protoplasm, one is seen with 
contracted contents and swollen cell-wall. This is the 
initial cell. 
The further development of the conceptacle as shown by 
section is marked by continued shrinking of the initial cell, 
and a gradual decomposition of the swollen substance which 
fills the cavity. This is accompanied by divisions in the 
basal and surrounding cells. In fig. 4 it will be noticed 
that the basal cell has divided in a plane parallel to the 
axis of the conceptacle. In the swollen mass which fills the 
cavity may be recognised irregular patches where the sub- 
stance has undergone alteration, accompanied by change in 
optical properties. This is still more evident in fig. 5, which 
is part of a transverse section of the thallus. 
Here the change of the substance filling the cavity has 
advanced so far that the unaltered portion immediately 
surrounding the remnants of the initial cell forms a 
central column of irregular outline. This stretches from 
the basal cell to the neck of the conceptacle, and is con- 
nected with the walls of the conceptacle by thin strings 
which, like itself, have remained as yet unchanged.^ 
' We must draw a distinction betweei\ these two stuffs : — that which 
forms the central column and the layer which overlies the whole surface of 
the plant ; and h, that which is formed at first in irregular patches, but 
which finally fills the greater part of the cavity of the conceptacle. The 
reactions, which are described later, bring to light a third body (c), which 
constitutes the outermost layers covering h at the exterior of the thallus 
(cf. reaction 6). The following observations will serve to point out their 
characteristics : 
1. The substance a has different optical properties from h, so that tliey 
are easily distinguished under the microscope ; a usually has a yellowish 
appearance. 
2. The substance a does not change volume to any marked extent on 
dehydration ; h, when dehydrated, contracts strongly, so that the concep- 
tacle, when mounted in alcohol, appears only partially filled. When water 
is added the contracted mass swells. 
3. Solution of iodine does not colour a, b, or c. 
4. When treated with a solution of chromic acid in water, the substance 
h becomes more transparent, and swells strongly, a is only slightly swollen ; 
and since its appearance is not much altered, it becomes more prominent, 
owing to the change in b. j 
5. With Schultz’s solution neither a, b, nor c give a blue colour, b swells 
strongly ; a is more resistant. [N.B. With this reagent the contents of 
the initial cell sometimes give the brown reaction of protoplasm; but this '* 
colouration is not constant, and probably depends upon the state of decom- 
position of the contents.] 
0. Treated with concentrated sulphuric acid, b is immediately dissolved ; 
a resists for a time, and is later dissolved ; but a central portion remains 
1 
