CHAP. II. 
POLLEN. 
153 
general a pentagonal or hexagonal figure more or less regular 
when cut across. In every cell, without excepting even those 
which constitute the superficial layer of the lobe, are certain 
loose particles, of such extreme minuteness that a magnifying 
power of 500 or 600 diameters is required to examine them sa- 
tisfactorily. I cannot compare them to anything better than 
to little transparent bladders, nearly colourless, more or less 
rounded, and of an equal size. I examined the cells of the 
lobe of the anther one by one ; and I affirm that, at this early 
period, there is no trace of either the cells of the anther or of 
the grains of pollen. The whole of the tissue is perfectly 
uniform. In a flowerbud, but little larger than the first, I re- 
marked on each side of the medial line of the slice a group, 
consisting of a few bladders, which were rather larger than 
the others, but otherwise like them. These larger bladders I 
propose to call pollen-cells, seeing that it is in their inside that 
the pollen is organised. In flowerbuds, from 1| to 2 lines 
in length, some remarkable changes were observable. The 
pollen-cells had become larger ; their granules were so much 
multiplied that they were grouped and packed in opaque 
masses, and wholly filled the cells. These cells and granules 
together constituted a greyish body, joined to the rest of the 
tissue by the intervention of a cellular membrane, — a sort of 
integument which, notwithstanding its organic continuity with 
the surrounding parts, was readily distinguishable ; for while 
the bladders of the surrounding parts lengthened parallel to 
the plane of the surface, and to the plane of the base of the 
anther ; those of the integument lengthened from the centre 
to the circumference. In anthers a little further advanced, 
the sides of the pollen cells, instead of being thin and dry as 
they had previously been, acquired a notable thickness, and 
their substance, gorged with fluid, resembled a colourless 
jelly. The cellular integument continued to adhere by its 
outer face to the lining of the cell of the anther, and by its 
inner face to the tissue formed by the pollen cells. Three and 
a half or four lines of length in the flower-bud corresponded 
with a phenomenon altogether unexpected. At first the 
thick and succulent wall of each pollen cell dilated, so as to 
leave a void between its inner face and the granules, not one 
