42 THE MICROSCOPICAL NEWS. 
by the coalescence of two masses of protoplasm differing very 
much from one another physiologically, and derived either from 
different parts of the same plant or from, what is perhaps more 
usual, a different plant altogether. 
The germ or female element concerned in the process, is a 
stationary, nucleated mass of naked protoplasm, lying within a 
comparatively large cell or cavity called the embryo-sac, which is 
a specially developed sub-epidermal cell of the ove, or incipient 
seed ; while the sperm or male elements are developed, generally 
in great numbers, within usually large sacs, or pouches, known as 
the anther cells. Each mass is small, usually more or less rounded, 
and becomes early invested with a cellulose cell-wall, that eventually 
differentiates itself into two layers, the inner remaining excessively 
thin and unmodified, while the outer gradually resolves itself into 
a surface of cork, specially adapted to act as a protection to the _ 
sperm protoplasm, which, sooner or later, is destined to become 
detached, and to lead, under favourable conditions, a short yet 
independent existence, removed from the structure within which it 
was generated. For it should be known, these sperm masses, or 
pollen grains, as they are called, have this special physiological 
function to perform in the reproductive economy of the plant ; 
they have to carry to the germ mass the necessary protoplasmic 
material, or highly specialised sexual food, which, by a process of 
transfusion, commingles with the female element, and enables it to 
start a process of growth, and series of developments, which end in 
the formation of an embryo. After this duty is performed, the 
activity of the pollen ceases, and it quickly dies. 
But in order to understand the exact mode by which the sexual 
act is affected, let us study as a type the poppy plant, and therein 
observe how the germ mass receives the fertilising contents pro- 
duced within the sperm or pollen grains. The ovules or organs 
containing the germ mass are themselves contained in special 
vessels the ovaries. The ovary is the youngest or central structure 
of the flower, and in the poppy it is large, oblong or subglobular, 
surmounted by a conspicuous aiscoid cap, composed of a number 
of radiating and cohering stigmas, which have surfaces specially 
developed for the reception of the pollen grains, and which also, 
at a certain period, secrete a stimulating fluid that tends to 
encourage the growth of the sperm protoplasm. 
Now in plants, like the pea, for example, we have an ovary of a 
much simpler nature than we find in our type. There, as every 
one knows, we have an elongated ovary which, during the forma- 
tion of the seeds, or peas, ripens into a pod. ‘The ovary has a 
single cavity, and may be looked upon as a leaf which has under- 
gone a special development, whereby its opposite lateral margins 
have become inflexed and cohering, while from the sutural line of 
