seum of Wormius, which had at one time occasioned much wonder'. It is not improbable that he knew how the Italian, whom he does not mention, though he is mentioned by Wor-, mius, and though he must certainly have been acquainted with his Zootomia, prepared his skeletons. I must however observe, that it is remarked by those who knew Ruysch, that he had read few books, and was very little versed in the literature of his profession. In the year following, Ruysch described more articles of the like kind, and gave figures of some pears prepared in this manner. In 1726, when Vater, professor at Wittenberg, expressed great astonishment at the fineness of his works, he replied, in a letter written in 1727, that he had at first caused them to be executed by insects, but that he then made them himself with his fingers. He repeated the same thing also in 1728, when he described and gave engravings of more of these curious objects. The progress of this invention is related in the same manner by Schreiber, in his Life of Ruysch. When the method of producing these skeletons became publicly known, they were soon prepared by others; some of whom made observations, which were contrary to those of Ruysch. Among these in particular were J. Bapt. Du Hainel, who, so early as the year 1727, described and illustrated with elegant engravings the interior construction of a pear+; Trew', in whose possession Keysler saw such skeletons în 1730; P. H. G. Mohring; Seba7; Francis Nicholls, an Englishman; Professor Hollmann9 at Göttingen, Ludwig 10, Walther, Gesner1 and others. Nicholls seems to have been 1 Adversariorum decas iii. in Ruyschii Opera Omnia Anat. Med. 2 A. Vateri Epist. ad Ruyschium de Musculo Orbiculari, 1727. Of employing different kinds of insects, particularly the dermestes, as they are called, for reducing animal and vegetable bodies to skeletons, Hebenstreit has treated in Program. de Vermibus Anatomicorum administris. Lips. 1741. Figures of the insects and of some of their preparations are added. 3 Acta Eruditorum, 1729, Febr. p. 63. ♦ Mémoires de l'Acad. des Sciences, ann. 1730, 1731, 1732. 7 Phil. Transact. 1730, ccccxvi. p. 441. 6 Ib. 8 Ib. ccccxiv. p. 371. Ib. cccclxi. p. 789, and cccclxiii. p. 796.-Commerc. Litter. Norimb. 1735, p. 353. 10 Institutiones Regni Vegetabil. In the part on Leaves. 11 Programma de Plantarum Structura. Lips. 1740, 4to, § 5, 6. 12 Dissertat. Phys. de Vegetabilibus, printed with Linnæi Orat. de Necessitate Peregrinat. intra Patriam. Lugd. B. 1743. the first who split the net of an apple- or a pear-tree leaf into two equal parts, though Ruysch split a leaf of the opuntia into three, four, and even five layers, as he himself says. In the year 1748, Seligmann, an engraver, began to publish, in folio plates, figures of several leaves which he had reduced to skeletons'. As he thought it impossible to make drawings sufficiently correct, he took impressions from the leaves or nets themselves, with red ink, and in a manner which may be seen described in various books on the arts. Of the greater part he gave two figures, one of the upper and an other of the under side. He promised also to give figures of the objects as magnified by a solar microscope; and two plates were to be delivered monthly. Seligmann however died soon after, if I am not mistaken; and a lawsuit took place between his heirs, by which the whole of the copies printed were arrested, and for this reason the work was never completed, and is to be found only in a very few libraries. Cobres says that eight pages of text, with two black and twenty-nine red copper-plates, were completed. The copy which is in the library of our university has only eight pages of text, consisting partly of a preface by C. Trew, and partly of an account of the author, printed in Latin and German opposite to each other. Trew gives a history of the physiology of plants and of leaf-skeletons; and Seligmann treats on the methods of preparing the latter. The number of the plates however is greater than that assigned by Cobres. The copy which is now before me contains thirty-three plates, printed in red; and besides these, two plates in black, with figures of the objects magnified. Of the second plate in red, there is a duplicate with this title, "Leaves of a bergamot pear-tree, the fruit of which is mild;" but the figures in both are not the same; and it appears that the author considered one of the plates as defective, and therefore gave another. The leaves represented in the plates are those of the orange-tree, lemon-tree, shaddock-tree, butcher's-broom, walnut-tree, pear-tree, laurel, lime-tree, ivy, medlar, chestnut-tree, maple-tree, holly, willow, white hawthorn, &c. I shall take this opportunity of inserting here the history of the art of raising trees from leaves. The first who made 1 Die Nahrungs-Gefässe in den Blättern der Bäume. Nurnb. 1748. this art known was Agostino Mandirola, doctor of theology, an Italian minorite of the Franciscan order. In a small work upon Gardening, which, as I think, was printed for the first time at Vicenza, in duodecimo, in the year 1652, and which was reprinted afterwards in various places, he gave an account of his having produced trees from the leaves of the cedar- and lemon-tree; but he does not relate this circumstance as if he considered it to be a great discovery. On the contrary, he appears rather to think it a matter of very little importance. His book was soon translated into German; and his account copied by other writers, such as Böckler and Hohberg, who were at that time much read. A gardener of Augsburg, as we are told by Agricola, was the first who imitated this experiment, and proved the possibility of it to others. He is said to have tried it with good success in the garden of count de Wratislau, ambassador at Ratisbon from the elector of Bohemia. But never was this experiment so often and so successfully repeated as in the garden of baron de Munchhausen, at Swob ber. A young tree was obtained there from a leaf of the Limon a Rivo, which produced fruit the second year. It was sent to M. Volkamer, at Nuremberg, who caused a drawing to be made from it, which was afterwards engraved, in order that it might be published in the third volume of his Hesperides; but as the author died too early, it was not printed. The exact drawing, as it was then executed at Nuremberg, and an account of the whole process employed in the experiment at Swobber, have been published by the baron de Munchhausen himself, from authentic papers in his grandfather's own writing*. No one, however, excited so much attention to this circumstance as the well-known George Andrew Agricola, physician at Ratisbon, who, with that confidence and prolixity which were peculiar to him, ventured to assert that trees could be propagated in the speediest manner by planting the leaves, after being steeped in a liquor which he had invented; and for the truth of his assertion he referred to his own experi 1 Many editions of this book may be found mentioned in Halleri Bibl Botan. i. p. 484; Böhmeri Bibl. Hist. Nat. iii. p. 679. 2 Haus- und Feld-Schule, i. 26. • Hausvater, vol. v. p. 662. * Georgica Curiosa, i. p. 787. ments1. Among the naturalists of that period none took more trouble to examine the possibility of this effect than Thummig, who endeavoured to prove that not only leaves with eyes left to them, could, in well-moistened earth, throw out roots which would produce a stem, but that leaves also without eyes would grow up to be trees. Baron Munchhausen, on the other hand, assures us, that according to the many experiments made in his garden, one can only expect young plants from the leaves of those trees which do not bring forth buds; that experiments made with the leaves of the lemon-tree had alone succeeded, but never those made with the leaves of the orange- or lime-tree; and that Agricola and Thummig had erroneously imagined that the leaves themselves shot up into trees, their middle fibre (rachis) becoming the stem, and the collateral fibres the branches. But the leaf decays as soon as it has resigned all its sap to the young tree, which is springing up below it. To conclude: It is probable that the well-known multiplication of the Indian fig, or Opuntia, gave the first idea of this experiment; for every joint of that plant, stuck into the earth, and properly nurtured, throws out roots and grows. As these joints were commonly considered to be leaves, people tried whether other leaves would not grow in the like manner. Luckily, those of the lemon-tree were chosen for this purpose; and what was expected took place. Thus from a false hypothesis have new truths often been derived; and thus was Kepler, by a false and even improbable opinion, led to an assertion, afterwards confirmed, that the periodical revolutions of the planets were in proportion to their distance from the sun. But the raising of trees from leaves was too rashly declared to be a method that might be generally employed; for it is certain that it now seldom succeeds. [Beckmann certainly overrates the value of these plantskeletons in assisting the acquirement of a knowledge of the anatomy of plants. By macerating plants in water, all but the woody fibres are decomposed by the putrefactive fermentation which ensues. From an examination of these, a knowledge of structure merely is attainable, which may be now * Versuch der Universal-vermehrung aller Bäume. Regensb. 1716, fol., or the edition by Brauser. Regensb. 1772. 2 Thummigii Meletemata. Brunsw. 1727, 8vo, p. 5. truly said to be thoroughly understood. It gives us no insight into its functions. The modern microscope has revealed to us the structure of all the components of vegetable tissues, and has most materially assisted in developing the functions of several; many, however, remain in the hands of the physiologist. Nevertheless, these plant skeletons exhibit the true course and arrangement of the woody fibres, and form most beautiful objects. The leaves are not the only parts which can be thus prepared; the petals of many plants are even more delicate and beautiful in their ligneous structure, as evidenced in the hydrangea and several others. Their preparation is exceedingly simple, but tedious, and can only be well effected by maceration in water, which frequently requires to be considerably prolonged. The pulpy half-decomposed portions are gradually removed by a camel-hair pencil, or other means, with great delicacy and care; they are finally washed and bleached, if necessary, with chloride of lime or soda. By washing in considerably diluted muriatic acid and water, all traces of this reagent are removed; they are then dried, and will keep for an indefinite period.] BILLS OF EXCHANGE I SHALL not here repeat what has been collected by many learned men respecting the important history of this noble invention, but only lay before my readers an ordinance of the year 1394, concerning the acceptance of bills of exchange, and also two bills of the year 1404, as they may serve to illustrate further what has been before said on the subject by others. These documents are, indeed, more modern than those found by Raphael de Turre' in the writings of the jurist Baldus, which are dated March 9, 1328; but they are attended with such circumstances as sufficiently prove that the method of transacting business by bills of exchange was fully established so early as the fourteenth century; and that 1 Disp. i. quæst. 4. n. 23. 2 Consil. 348. |