Essays on the Microscope / Containing a Practical Description of the Most Improved Microscopes, a General History of Insects, etc., etc.

by George Adams

Anisum.

Fig. 8 and 9. Pimpinella A. Linn. Anise. Two of these seeds grow together upon one little stalk; when they are pulled asunder, they appear to have a flat and a convex surface. On the convex surface, Fig. 8, each seed has three ribs placed at equal distances from one another, which are porous and a little rough, being of a straw-colour; and the spaces between them are also rough and porous, but of an olive-colour. The flat surface, Fig. 9, has a white ridge running longitudinally from its basis to the apex in the middle; this white ridge or line serves to cling to the stilus, upon which it sticks. The stilus is also white, and has the same contexture with the ridge, and is bifid, in order to support two seeds with their flat sides together, which keeps them the more compact and less liable to injuries than if a single seed stuck on. It is certain, a single stilus would do as well to support two seeds as the bifid one, for even the two stick together as if single, if there was not a necessity for a double stilus, for a very important reason; which is, that when the seeds are ripe, they would stick on a single one, till the time of their being scattered about would pass, which would be a detriment to their propagation; but the stilus being double, and of a springy nature, the two parts are glued together, as long as moisture remains about the seeds capable of keeping them together; but when the seeds are grown ripe and dry, then this moisture is exhaled, and the stilus, as well as the flat surfaces of the seeds, begin to contract from their former plumpness; the stilus first begins to split asunder, and thereby separates the two surfaces of the seeds, each of which sticks loosely to its particular limb of the stilus; till at length the remaining moisture exhaling more and more, it grows rigid, and cracks with a blast of wind, and so the seed is scattered or sown in the ground in its due time. This is a most excellent provision of nature, and highly worth regard.

When the two seeds are sticking together, they have a round end which is the basis, and grow smaller by degrees upward, till they become an apex, having upon each seed a kind of fungous or bulbous corona, which is the umbilicus of the seed; and the shape of the two together may be compared to that of a given fig reversed. The parenchyma of these seeds is that of a pale greenish olive-colour. They are more exactly of a size than most other seeds, and are each one-eighth part of an inch long, and more than half that breadth.

Fœniculum Dulce.

Fig. 10 and 11. Anethum F. Linn. Sweet Fennel. In viewing these seeds, they do not look much unlike one species of the cucumber in general, some of them being thicker and longer than others, and some straighter; but upon applying the microscope, the ridges appear high, and form deep furrows.

Two of these seeds grow together upon the same little stalk, which is divided, like that of the anise seed, into a double or bifid stilus, in the same manner, and for the same reasons; when the two are pulled asunder, they appear to have a flat surface, Fig. 10, and a round and ridged one, Fig. 11. On the former, these characters are conspicuous: viz. 1. The whitish cortex or covering of the seed shews its edge distinctly. 2. Withinside this edge a white fungous substance appears running parallel to, and in close contact with it, on each side from end to end, being both together about one-third of the breadth of the seed; and between these, in the center, there appears a dark brown elliptical substance, which, upon separating the cortical and fungous coverings, appears to be a nucleus, whose internal substance is of an olive colour and something succulent. On the external surface there appears three high ridges, and when the flat faces of the seeds are close together upon the stilus, so as to seem but one, these three ridges on each seed and the two edges of each meeting firmly together, form eight regular ridges equally divided upon that round body that we have before said to resemble a cucumber. The extremity which is fixed to the stem is smaller than the other; the latter has a fungous kind of process arising from the body of the seed, which is the umbilicus of the seed. The ridges are of a light straw-colour, and the bottoms of the sulci they form are darkish. A middling seed is somewhat more than two-eighths of an inch long, and above half that breadth.

Grana Paradisi.

Fig. 12 and 13. Amomum G. P. Linn. Grains of Paradise. These seeds are of an irregular form, but may be said to have a basis and apex; the basis is generally so flat as to render it capable of standing well upon it; the sides consist of several flats and angles, and the apex looks very much like the mouth of a purse drawn or gathered up close together.

The body of the seed is of a reddish brown colour, the surface much granulated and rough; and the apex, which is its umbilicus, degenerates from this reddish brown colour into a yellow, appearing in little oblong ridges or plates.

Upon making a transverse section of this seed, a most beautiful appearance presents itself; the external cortex is very thin, and retains the same colour through its substance with the outer surface; this incloses a black, porous, pitchy substance, which is much thicker than the cortex, in close contact with it, and at the angles of the seed is pretty considerable. Next to this the parenchyma appears, as white as the finest white salt, and radiated from the center outward; and in this transverse section seems to have a round hole in the center of one of the divided parts, and a process answerable to it in the other. If a longitudinal incision be made through the middle, the appearance will be as in Fig. 13, when the center of the white parenchyma appears exactly like a modern vinegar glass, commonly called a cruet, the bottom of which tends obliquely towards the basis, and the top towards the apex of the seed. The surface of this part looks polished, and the colour is a yellowish olive; nor does it look unlike a gummy or resinous body; however, we cannot be certain what its substance is, notwithstanding its great resemblance to that kind of matter. The white parenchyma is very singular, being almost divided into two lobes by this little cruet, whose top runs up into or is lost in a remarkable circular part, which has a rising towards the umbilicus of the seed in form of an acorn, and this rising stands in the open place, into which the pursy umbilicus leads. As to its natural dimensions, an ordinary seed is somewhat more than the eighth of an inch long, and about an eighth thick.