596 



SUPPLEMENT 



with which the student is so greatly interested, 

 and amused, owes almost its very existence 

 to the microscope. This observation will be 

 lound to apply in an especial manner both to 

 the cellular and vascular tissues of plants. 

 The membraneous cellules of cellular tissue 

 are sometimes not more than 1-1 000th of an 

 inch in diameter ; and those of the ordinary 

 size, are about l-200th or l-300th. How then 

 is it possible that we could become acquainted 

 with their forms and arrangement but by the 

 aid of the microscope? And so with respect 

 to vascular tissue : it is absolutely indispensa- 

 ble toward acquiring an accurate knowledge 

 of the structure and forms of these membrane- 

 ous tubes, and of the spiral, or annular, fibre 

 that surrounds them. A knowledge of the 

 fructification, if I may so express myself, of 

 that numerous and curious class of plants, the 

 Acrogens, could not be obtained without it; 

 nor could the existence of many of them, such 

 as the Fungi, Algas, and some of the Musci, 

 be proved. By its powers, even the ashes of 

 vegetables may be seen to contain the decisive 

 characteristics of organic structure ; and the 

 long debated question of the antiquarian, 

 whether the " fine linen of Egypt" in the times 

 of the Pharaohs, was of linen or cotton fibre, 

 seeing the latter is now indigenous to that 

 country, is for ever set at rest." 



But, not to insist in this place on the aid 

 afforded by the microscope to the professed 

 botanist or the scientific inquirer, let us glance 

 at those simple yet highly interesting and 

 pleasing observations, which appeal so forcibly 

 to every one who has a mind constituted to 

 relish and enjoy the beauties of nature. In 

 an ordinary survey of flowers, we found our 

 admiration on the beautiful shape and texture 

 of the petals, their number, colour and arrange- 

 ment ; and the singular or striking disposition 

 of the stamina and other parts reposing in the 

 cup of the blossom. But when we take a 

 single flower and subject it in detached parts 

 to microscopic, examination, what a fund of 

 pleasing knowledge is opened to us ! The 

 velvet surface of the petals is resolved into a 

 fabric which no human art can imitate ; and 

 the stamens and adjacent parts when examined 

 in detail, exhibit formations which could not 

 have been conceived to exist in so small a 

 space. Every flower has microscopic beauties 

 peculiar to itself; and it would occupy the 

 leisure of an extended life, to make one min- 

 utely acquainted with the floral products of 

 the humblest village garden. Then, again, 

 what a variety of shape and character is to be 

 observed in seeds ; some with beautiful shining 

 surfaces, others most singularly marked and 

 figured, or strangely peculiar in form, or pro- 

 vided with curiously wrought appendages, 



vel all strikingly adapted to further ami assist 



the reproduction of the plants to which they 

 respectively belong. The fibres, veins, pe- 

 culiarities of surface, &c., of the plant leaves 

 demand careful investigation ; and the young 

 wood of the shoots is likewise worthy of being 

 minutely examined. A thin transverse sec- 

 tion of the latter discovers under the micros- 

 cope a structure resembling, but far surpassing, 

 the richest lace work. It is time, however, 

 to leave these desultory remarks, and proceed 

 with our subject in an orderly manner. 



We have before alluded to the active mole- 

 cules of matter in connection with the mineral 

 kingdom, and we are now briefly to notice the 

 same phenomenon of atomic activity in vege- 

 tables. Indeed, it was during a course of ex- 

 perimental observations on the latter sub- 

 stances, that this phenomenon was first wit- 

 nessed by Robert Brown, Esq. F.R.S. Hav- 

 ing found that the pollen of plants, when 

 suspended in water, exhibits a most remarkable 

 activity, evidently resulting from other causes 

 than the agitation of the fluid or the breath of 

 the observer, he naturally concluded, that the 

 minute particles of inorganic bodies might 

 present similar appearances, if similarly sus- 

 pended. 1 This conclusion is proved to be cor- 

 rect. So far as the writer has observed, there 

 is no difference between the motions of mineral 

 and vegetable molecules, beyond what may 

 be explained by the different principles on 

 which these two species of atoms are presumed 

 to combine, for the formation of inorganic and 

 organic bodies Our space will not permit 

 us to speculate on this point of identity between 

 the vegetable and mineral kingdoms ; it must, 

 however, strike the reflecting reader as a re- 

 markable circumstance, that the minutest 

 atoms of vegetable and mineral bodies are con- 

 trolled by one common law ; and he may be 

 led to the inference that probably organic and 

 inorganic bodies are produced by one and the 

 same principle, modified by secondary agen- 

 cies. There is, notwithstanding, this broad 

 and decisive distinction between organic and 

 inorganic structures ; the former are mere ag- 

 gregations of atoms, the latter are laboratories, 

 in which complicated operations are continu- 

 ally going forward to prepare matter, so that 

 it may assimilate with and enter into their 

 constitution. 



The circulation of the fluids in plants seems 

 to link them with animal existences ; but we 

 find, on close examination, that the motion of 

 vegetable fluids differs widely from that of 

 the blood. Blumenbach observes ; " How- 

 ever varied the rtticular and other connections 

 of the vessels may be, no relation can be 



1 This molecular activity is exhibited, not in the vege- 

 table dust, palpable to the naked eye, and usually named 

 the pollen, but in (he particles of the true farina hereafter 

 to be noticed. 



