62 
consisted of a filament, sometimes sessile, and the anther—a cellular 
organ containing the Pollen. The pistil, composed of three parts, 
though apparently foreign to the subject, must be considered, if we 
wished rightly to understand the question. 
Its three parts were the ovary, composed of carpels, containing the 
rudimentary structure of the seed ; the sty/e, a stem rising from the 
ovary, and terminated by the sigma, a very important organ, because 
the Pollen cells falling .on it performed a very marvellous function. 
The stigma had a fleshy substance, possessing the power of secreting 
a sticky, honey-like fluid, by means of which the Pollen became 
adherent. ; 
The Pollen Grains, which were produced in great abundance, 
resembled a yellow or other coloured dust, very diverse in form, but 
generally either spherical or oval in shape, though other geometrical 
forms were known. Their surface, under a low power, was seen to be 
corrugated, reticulated, depressed, &c., and covered over with points, 
fissures, or slits. Looked at anatomically, it consisted of an outer 
covering composed of two coats and the cell contents. The inner 
coat was of extreme delicacy and fineness. Within was a fluid, 
containing minute granules. 
Physiologically, the Pollen Grains were very important. As soon 
as the pistil and stamen were matured and prepared to co-operate with 
each other, the lobes of the anther became fissured, when the Pollen 
Grains were shed abroad, and fell or were conveyed to the summit of 
the Pistil. Here a remarkable phenomenon occurred, in which it was 
seen that the Pollen Grains were endowed with a very striking character, 
as manifested by the results ; for they at once underwent a change. 
From the fissures or slits the membrane protruded, and, gradually 
advancing, formed itself into a delicate tube from the 1-4,000 to 
1-7,000 of inch in diameter, which, penetrating through the cellular 
tissue, at whatever point it became adherent, and not necessarily, as 
some thought, along the axis of the pistil, it insinuated itself through 
the whole length of the pistil,—sometimes several inches long; in 
some cases this was accomplished in from three to four hours ; in 
others it took weeks; but eventually finding its way into the ovary con- 
taining the primordial seeds. Here, ceasing to elongate, the extremity 
of the tube reached that part of the ovule called the mcropyle, when, 
having performed its office, it died. 
Changes now took place in the ovule, which, but for the influence of — 
_the Pollen Grains, would have remained sterile, and have gone for 
