an odd one, pointed, serrated, veined, standing upon footstalks, of an oval or oblong shape, and bright green colour. The flowers grow in close thick brauched spikes, and open in May and June. In the specimens generally figured, the flowers are all hermaphrodite; the corol divided into four narrow whitish segments, somewhat longer than the stamens; the two filaments tapering, and crowned with large furrowed erect anthers; the germen oval, and a little com. pressed; the style short and cylindrical; the capsule is long, flat, membranous, and contains a single flat pointed seed. This tree is a native of the southern parts of Europe, particularly of Sicily and Calabria*. It was first introduced into England about seventy years ago, by Dr. Uvedale †; and at present adorus many of the gardens of this country. The Ormus is not the only species of ash which produces Manna; the rotundifolia and excelsior, especially in Sicily, also afford this drug, though less abundantly. Many other trees and shrubs have likewise been observed, in certain seasons and situations, to emit a sweet juice, which concretes on exposure to the air, and may be considered of the manna kind. In Sicily the three species of the Fraxi The Ornus is observed by Dr. Cirillo to be very common on the famous mountain Garganus, so that the words of Horace may still apply; + Vide Hort Kew. -aut Aquilonibus "Manna a part of the sugar so 66 Dr. Cullen is certainly right in supposing universally present in vegetables, and which exudes on the surface of a great number of them;" the qualities of these exudations he thinks are very little if at all different." The principal trees known to produce these mannas in different climates and seasons, are the larch, (vide Murray Ap. Med. i. p. 17.) 144,) the fir, (Lac V. Engerstrom in Physiogr. Salskapets Handl. Vol. i. P. 3. p. the orange, (De La Hire Hist. de l'acad. d. sc. de Paris, 1708.) the waluut, (Hal. Stirp. Helv. N. 1624.) the willow, (Mousset in du Hamel. Physique des arbres, P. i. p. 152.) the mulberry, (Micheli in Tragioni Tozzetti Viaggi, Tom. 6. p. 424.) oaks, situated between Merdin and Diarbekir (Niebuhr Beschreib. v. Arab. p. 145. Otter, Voyage en Turquie et en Perse, Vol. 2. p. 264.) also oaks in Persia near Khounsar (Otter. 1. c.) the al hagi Maurorum, or the hedysarum alhagi of Linnæus; of this manna Dr. Fothergill presented a specimen to the Royal Society, which he considered as the Tereniabin of the Arabians, (Phil. Trans. Vol. 43. p. 87.) the cistus ladaniferus in some parts of Spain produces a manna, which, in its recent state, has no purgative quality, and is eaten by the shepherds: so that some fermentation seems necessary to give it a cathartic power, Vide Dillon's Travels through Spain, p. 127.) nas, mentioned above, are regularly cultivated for the purpose of procuring manna, and with this view are planted on the declivity of a bill, with an eastern aspect. After ten years growth, the trees first begin to yield the manna, but they require to be much older before they afford it in any considerable quantity. Although the manna exudes spontaneously upon the trees, yet in order to obtain it more copiously, incisions are made through the bark, by means of a sharp crooked instrument; and the season thought to be the most favour. able for instituting this process, is a little before the dog days commence, when the weather is dry and serene. The incisions are first made in the lower part of the trunk, and repeated at the distance of an inch from the former wound, still extending the incisions upwards as far as the branches, and confining them to one side of the tree, the other side being reserved till the year following, when it undergoes the same treatment. On making these incisions, which are of a longitudinal direction, about a span in length, and nearly two inches wide, a thick whitish juice immediately begins to flow, which gradually hardens on the bark, and in the course of eight days acquires the consistence and appearance in which the manna is imported into Britain, when it is collected in baskets, and afterwards packed in large chests *. Sometimes the manna flows in such abundance from the incisions, that it runs upon the ground, by which it becomes mixed with various impurities, unless prevented, which is commonly attempted, by interspersing large concave leaves, stones, chips of wood, &c. The business of collecting manna usually terminates at the end of September, when the rainy season sets in t. * La manne est le principal revenu de ce pays & de quelques autres qui en sont voisins. Il monte dans une bonne année a vingt-cinq mille Louis d'or. Houel Voyage Pittoresque, tom. 1. p. 53. + This account is taken from Houel Voyage Pittoresque, and Sestini Lettre della Sicilia, and related by Murray; to which we shall subjoin Dr. Cirillo's account, communicated to the Royal Society. Vide Vol. 60. p. 233. "The manner in which the manna is obtained from the Ornus, though very simple, has been yet very much misunderstood by all those who travelled in the kingdom of Naples; and among other things they seem to agree, that the best and purest manna is obtained from the leaves of the tree; but this, I believe, is an opinion taken from the doctrine of the ancients, and received as an incon testible observation, without consulting nature. I never saw such a kind, and all those who are employed in the gathering of the manna, know of none that comes from the leaves. The manna is generally of two kinds; not on account of the From this account it is evident, that the manna is the succus proprius of the tree; any arguments therefore brought to combat the ancient opinion of its being a mel aërium, or honey.dew, are wholly unnecessary: that, with which the Israelites were so peculiarly favoured, could only have been produced through miraculous means, and is consequently out of the province of the natural historian.— Manna is generally distinguished into different kinds, viz. the manna in tear, the canulated and flaky manna, and the common brown or fat manna. All these varieties seem rather to depend upon their respective purity, and the circumstances in which they are obtained from the plant, than upon any essential difference of the drug when the juice transudes from the tree very slowly, the manua is always more dry, transparent, and pure, and consequently of more estima. tion; but when it flows very copiously it concretes into a coarse brown unctuous mass; hence we have a reason, why, by applying intrinsic quality of them being different, but only because they are got in a different manner. In order to have the manna, those who have the management of the woods of the Orni in the months of July and August, when the weather is very dry and warm, make an oblong incision, and take off from the bark of the tree about three inches in length, and two in breadth; they leave the wound open, and by degrees the manna runs out, and is almost suddenly thickened to its proper consistence, and is found-adhering to the bark of the tree. This manna, which is collected in baskets, and goes under the name of manna grassa, is put in a dry place, because moist and wet places will soon dissolve it again, This first kind is often in large irregular pieces of a brownish colour, and frequently is full of dust and other impurities. But when the people want to have a very fine manna, they apply to the incision of the bark, thin straw, or small bits of shrubs, so that the manna, in coming out, runs upon those bodies, and is collected in a sort of regular tubes, which gives it the name of manna in cannoli, that is, manna in tubes: this second kind is more esteemed, and always preferred to the other, because it is free and clear. There is indeed a third kind of manna, which is not commonly to be met with, and which I have seen since I left Calabria: it is very white, like sugar; but as it is rather for curiosity than for use, I shall say no more of it. The two sorts of manna already mentioned undergo no kind of preparation whatsoever, before they are exported; sometimes they are finer, particularly the manna grassa, and sometimes very dirty and full of impurities; but the Neapolitans have no interest in adulterating the manna, because they always have a great deal more than what they generally export; and if manna is kept in the magazines, it receives often very great hurt by the southern winds, so common in our part of the world. The changes of the weather produce a sudden alteration in the time that the manna is to be gathered; and, for this reason, when the summer is rainy, the manna is always very scarce and very bad." straws and other substances to receive the flowing juice, the manna becomes much improved: Houel, who tasted the manna when flowing from the tree, found it much bitterer than in its concrete state; this bitterness he attributes to the aqueous part, which is then very abundant, of course the manna is meliorated by all the circumstances which promote evaporation. According to Lewis," the best manna is in oblong pieces, or flakes, moderately dry, friable, very light, of a whitish or pale yellow colour, and in some degree transparent: the inferior kinds are moist, unctuous, and brown. Manna liquifies in moist air, dissolves readily in water, and, by the assistance of heat, in rectified spirit. On inspissating the watery solution, the manna is recovered of a much darker colour than at first. From the saturated spirituous solution, great part of it separates as the liquor cools, concreting into a flaky mass, of a snowy whiteness, and a very grateful sweetness." Manna is well known as a gentle purgative, so mild in its operation, that it may be given with safety to children and pregnant women; in some constitutions however it produces troublesome flatu. lencies, and therefore requires the addition of a suitable aromatic, especially when given to an adult, where a large dose is necessary; it is therefore usually actuated by some other cathartic of a more powerful kind. The efficacy of manna is said, by Vallisnieri, to be much promoted by cassia fistularis, a mixture of the two purging more than both of them separately; it is therefore very properly an ingredient in the electuarium e cassia. [Woodville, Cullen. Hort. Kew. SECTION. II Senna-Tree. Cassia Senna.-LINN. CASSIA in the Linnæan system is a voluminous genus, comprehending not fewer than fifty-four or fifty-six species; of these there are two that furnish useful materials in medicine. C. senna, which belongs to the present section, and C. Fistula, which will be described in the next. The root of this plant is annual: the stalk is strong, smooth, branched, erect, and rises about two feet in height: the leaves stand in alternate order, and at their base are placed narrow pointed sti pulæ each leaf is composed of several pairs of oval or elliptical point. ed nerved sessile pinnæ, of a yellowish green colour: the flowers are yellow, and produced successively in long axillary spikes: the calyx consist of five leafits, which are narrow, obtuse, concave, unequal, and deciduous: the corolla is composed of five petals, which are roundish, concave, entire, and of unequal size: the filaments are ten, of which the three undermost are longer than the others, and fur. nished with large beaked curved antheræ; the germen stands upon a short pedicle, and is long, compressed, and supplied with a short style, which is turned inwards, and terminated by an obtuse stigma: the seeds are brown, roundish, flat, and produced in a short compressed curved pod, divided by transverse partitions. The flowers appear in July and August. Senna is a native of Egypt: it also grows in some parts of Arabia, especially about Mocha; but as Alexandria has ever been the great mart from which it has been exported into Europe, it has long been distinguished by the name of Alexandria Senna, or Sena.-Mons. Blondel, who was French Consul at several sea ports of the Levant, informs us, that the true senna grows only in the woods of Ethiopia and in Arabia; for that the seuna, which was brought from Saide and Tripoli was carried there by the caravans, and the negative tes timony of Alpinus, who in his Lib. de plantis Egypti does not notice senna, may seem to strengthen this opinion. But as Hasselquist found this plant growing spontaneously in Upper Egypt, the asser tion of Mr. Blondel is not to be implicitly received. The Senna Italica, or blunt-leaved senna, is a variety of the Alexandrian species, which by its cultivation in the south of France, (Provence) has been found to assume this change; it is less purga. tive than the pointed-leaved senna, and is therefore to be given in larger doses; it was employed as a cathartic by Dr. Wright at Ja. maica, where it grows on the sand banks near the sea. Senna appears to have been cultivated in England in the time of Parkinson (1640); and Miller tells us, that by keeping these plants in a hot-bed all the summer, he frequently had them in flower, but adds, it is very rarely that they perfect their seeds in England. There can be little doubt however but that some of the British possessions may be found well enough adapted to the growth of this ve getable, and that the patriotic views of the Society for encouraging |