Medical Officers of the Army of India.
35
tinguished from other elements of the tissue. by their crimson-red colour. They
are also quickly soluble in water, for in sections cut in Water they are generally
missed, whilst they are always very abundantly present in sections cut and
examined in glycerine. These granules vary very greatly in size from about
16 µ in diamater to 4 µ (Figs. 2 and 3, Plate IV). The smaller ones are more
abundant than the larger, which appear to be compounded of several smaller
ones (Fig. 3, Plate IV). The central hypertrophied pith cells do not contain
these large grains, but with Schultze's solution a number of fine, minute, deep-
blue granules may be seen throughout them.
Spermogonia.—These present the usual characters. A fully ripe one mea-
sured 0.178 m.m. in breadth and depth ; a younger, still unopened one, 0.104 m.m.
in both directions. They have a radiating pencil of hairs on their summits
suring about 68 µ in length. The spermatia are very minute, oval; rod-like, or
often pyriform bodies, and with certain, focussing present a minute black point
in their centres. They vary in length from 3 to 4 µ, and are about
1 µ in breadth. The spermogonia do not exhibit the same proneness to develope
in the fibrovascular tissues as do the æcidia. They occur mostly in the paren-
chymatous tissue of the leaf. In the spermogonial stage, and when as yet there
are no signs of the formation of æ cidia, the thickness of the affected portions
of the leaf-blade is almost exactly double that of the normal leaf-blade. The
parenchyma cells of the involved parts are filled with large granules similar to
those above described.
Æcidia.—The young æcidia filled with spores but still unopened are spherical,
but often slightly compressed from above, their breadth-exceeding their depth a
little. Such aecidia measure from 0.175 m.m. in breadth and 0.139 in depth, to
0.294 m.m. in depth and breadth. Large fully ripe arid open ones measure as
much as 1.061 m.m. x 0.353, and even more. The æcidia are enclosed by a
peridium of a single layer of flattened cells which measure on an average 20 µ in
diameter. These cells are considerably thickened on their outer sides (Fig. 9
,
Plate V), and with chlor. zinc. iod. become brick-red. When seen from the surface,
they are polygonal (Fig. 20, Plate II). They are so arranged that the upper edge
of each cell is overlapped by the long, bevelled, lower edge of the cell immediately
above it. The arrangement is therefore imbricate. The internal surfaces of
these cells are densely studded with characteristic tubercles. In section these
cells measure 20 µ in len gth by 20 µ in depth, but 6 µ of the latter are due to the
outer thickened wall. The cells lower down are generally about 14 µ in length
. Outside the peridium is a layer of convoluted mycelial elements.The æcidio-
spores are given off in extremely long rows from a series of basidia arranged very
regularly, their upper ends forming a level base. These basidia are on an
average 40 µ i n l engt h and frot h 2 t o 2 5 µ i n d i a m e t e r . T h e y r e s t u p o n a b a s e
of convoluted fibres forming a pseudo-parenchymatous mass. This together
with the basidia and the lower younger æcidiospores take carmine stains well.
F 2