.'22 ON THE BONES, &c. 



climate has its indigenous plants as well as its indigenous animals) should so 

 frequently meet together in the same region 1 that those which naturally be 

 long to the Cape of Good Hope should be found wild in New-Holland ? and 

 those of Africa on the coast of Norway ? and that the Floras of every climate 

 under the heavens should consociate in the stoves and gardens of our own 

 country 1 It is the imperishable nature of the integument that surrounds 

 their seeds by which this wonder is chiefly effected. Some of these seeds 

 are provided with little hooks, and fasten themselves to the skins of animals, 

 and are thus carried about from place to place ; others adhere by a native 

 glue to the feathers of water-fowls, and are washed off in distant seas ; 

 while a third sort are provided by nature with little downy wings, and hence 

 rise into the atmosphere, and are blown about by the breezes towards every 

 quarter of the compass. Of this last kind is the light seed of the betula alba, 

 or birch-tree ; which, in consequence, is occasionally seen germinating on the 

 summit of the loftiest rocks and the tops of the highest steeples.* But it is to 

 man himself that this dissemination of plants is chiefly owing. He who in 

 some sort commands nature who changes the desert into a beautiful land- 

 scape who lays waste whole countries, and restores them to their former 

 fruitfulness-^-is the principal instrument of enriching one country with the 

 botanical treasures of all the rest. Wars,, migrations, and crusades, travel, 

 curiosity, and commerce, have all contributed to store Europe with a multi- 

 tude of foreign productions, and to transplant our own productions into foreign 

 quarters. Almost all the culinary plants of England, and the greater number 

 of our species of corn, have reached us from Italy or the East ;f America 

 has since added some ; and it is possible that Australia may yet add a few 

 more. 



The utmost period of time to which seeds may hereby be kept, and be en- 

 abled to retain their vital principle, and consequently their power of germina- 

 tion, has not been accurately determined ; but we have proofs enough to show 

 that the duration may be very long. Thus, M. Triewald relates that a paper 

 of melon-seeds, found in 1762, in the cabinet of Lord Mortimer, and appa- 

 rently collected in 1660, were then sown, and produced flowers and excellent 

 fruit ;J and Mr. R. Gale gives an instance of a like effect from similai seeds 

 after having been kept thirty-three years. 



M. Saint-Hilaire sowed various seeds belonging to the collection of Ber- 

 nard de Jussieu, forty-five years after the collection had been made. They 

 consisted of three hundred and fifty distinct species ; of these many, though 

 not the whole, proved productive. In some the cotyledon appeared to have 

 nearly, but not entirely, perished : in which, therefore, though the seeds 

 swelled, and promised fairly at first, they died away gradually. And as it is 

 a well-known fact that melons improve from seeds that have been kept for 

 two or three years, he conceives that in this case the cotyledons have been 

 ripened during such period. || 



Animal seeds or eggs, when perfectly impregnated, appear capable of pre- 

 servation as long. Bomare, indeed, affirms, that he himself found three eggs, 

 which, protected from the action of the air, had continued fresh in the wall 

 of a church in which they must have remained for a period of three hundred 



The integument which covers seeds, eggs, insects, and worms, seldom con- 

 sists of more than two distinct layers, and is sometimes only a single one ; 

 but in the four classes of red-blooded animals it consists almost uniformly 

 of three layers, which are as follows : first, the true skin, which lies lower- 

 most, is the basis of the whole, and may be regarded as the condensed exter- 

 nal surface of the cellular substance, with nerves, blood-vessels, and absorbents 

 interwoven in its texture ; secondly, a mucous web (rete mucosum), which gives 

 the different colours to the skin, but which can only be traced as a distinct 



* There is an interesting article on this subject pnblished long since the above was delivered; an accoun. 

 of which may be found in the Journal of Science and the Arts, No. vii. p. 3. 

 t Willdenow, Principles, <fcc. 357. J Phil. Trans, vol. xlii. $ Ib. vol. xliii. 



|| lilloch's Phil. Mag. vol. xlii. p. 208, article of M. Saint-Hilaire. IT Dictionnaire, art. Oeuf 



