46 



BOTANY. 



Vegetable 

 Physiolo- 

 gy- 



Reproduc- 

 tion. 



Sensibility 



Animals. 



Vegeta- 

 bles. 



blc, that we cannot, with the 'knowledge we now 

 possess, fix on any solitary character which may not 

 be controverted, or which, indeed, may not be found- 

 ed, in some degree, on an unproved assumption. It 

 is not, therefore, at all wonderful, that every at- 

 tempt at a legitimate definition should have failed. 

 Of late, physiologists have taken a wider range, 

 and have instituted a parallel between the general 

 characters of animals and of vegetables, instead of 

 confining themselves to one or two individual facts. 

 That this parallel description, which we shall adopt, 

 may be more readily understood, it will be expedient 

 to sketch, rapidly, all the properties common to both 

 kingdoms ; and then we shall be better enabled to 

 compare those peculiar to each. 



That all animals and vegetables exliibit phenomena 

 which we refer to a living principle, is an unde- 

 niable fact. Without investigating the nature of 

 this living principle, it is sufficient for our purpose 

 that certain phenomena are exhibited by organised 

 matter, which essentially distinguish it from that 

 which is unorganised. The most ignorant, as well as 

 the most subtle, of mankind knows perfectly, that 

 there is a most important difference between the man 

 by whose benevolence he might have been soothed, 

 or by whose eloquence he might have been animated, 

 and the same individual when he has ceased to live. 

 It is of little moment wherein the nature of this dif- 

 ference consists ; the effects are cognizable by our 

 senses. In the same manner, vegetables may be ei- 

 ther living or dead ; and although their vital actions 

 ure not evident as those of animals, yet a little care- 

 ful examination will soon convince us of their exist- 

 ence. If by external violence, by electricity, by 

 heat, or by any'other means, the life of a plant be 

 destroyed, the various living functions will cease, 

 and the parts of the plant will become subject to 

 the laws of chemical decomposition, which in all 

 cases succeeds the cessation of life. 



Vegetables, as well as animals, possess, to a certain 

 extent, the power of reproducing certain parts which 

 have been destroyed. Contractility, elasticity, and 

 irritability, are also characters of all organised mat- 

 ter, as has been sufficiently shewn by various experi- 

 ments. 



Sensibility appears to be confined to animals ; for 

 no experiments, except those of Rafn on the Mimosa 

 sensitiva, afford the -least suspicion of its existence 

 in vegetables. And eten these experiments are so 

 liable to error, besides being isolated, that no general 

 conclusion can be fairly drawn from them. Such are 

 the leading properties peculiar and common to all 

 organised bodies. We shall now proceed to contrast 

 those properties in which they differ, as concisely and 

 as fairly as the subject will permit. 



The food of the animal consists of organised 

 matter, which is introduced into its system by a 

 mouth ; its excrements are carried off by an intestinal 

 canal ; it is farther characterised by brain, nerves, and 

 by evident signs of sensibility, and of voluntary mo- 

 tion. The vegetable, on the other hand, is nourish- 

 ed by inorganic matter, which it receives through 

 the medium of roots ; it does not indicate sensibility, 

 or exert voluntary motion. In addition to the above 

 characters, which are of primary importance, some 



philosophers have attempted to make the organs of Vegeu 

 generation the criterion of distinction. This, how- PkyiJj 

 ever, appears to be fanciful and unsatisfactory. It 

 is not to be expected that every vegetable and ~~ v "" 

 Bninial will givt- evident proofs of all of the above 

 characters ; it will be enough if they possess the more 

 striking and obvious. 



Chemical anatysis points out the constituent princi- Analysi 

 pies of vegetables, which differ from those of animals : 

 the former being chiefly composed of carbon, hydro- 

 gen, and oxygen ; while the latter also contain azote. 

 Various compounds, formed of these simple consti- 

 tuents, are also found in vegetables. For a cor- 

 rect account of them, we beg leave to refer to the 

 article CHEMISTRY. Plants are composed of various 

 individual parts, and of the organs proper to those 

 parts. We shall describe each of these ; and imme- 

 diately after each description, give some account of 

 the functions it performs. 



SECT. I. On the Seed. 



The seed, though the last production of the Seed, 

 mature plant, is the means by which a similar plant 

 is reproduced. This is the case in the whole range 

 of the vegetable kingdom, as has been well proved 

 by the valuable experiments of Hedwig, and others. 



It therefore will be proper to commence our 

 skstch of the anatomy and physiology of plants, with 

 this most important part ; and we shall begin with some 

 account of the progress which is made from the first 

 to the perfect formation of the seed. Mrs Ibbetson 

 has, with much industry, examined its progress from 

 the earliest period of its existence, and detailed the 

 results of her observations in several papers in Nichol- 

 son's Journal ; but our limits do not permit us to 

 give so full an account of them as would do her justice ; 

 and as most of the observations were made with a 

 highly magnifying solar microscope, we shall confine 

 ourselves chiefly to the less minute and sufficiently 

 accurate details of other physiologists. According to 

 their observations, soon after the formation of the 

 external membranes, the albumen and vitellus are 

 deposited ; in some cases both are deposited, in others 

 only one. In the midst of this albuminous matter is 

 the small rudiment of the plant, called the corcle, 

 with which it freely communicates, by means of ves- 

 sels which support and nourish it. The inner struc- 

 ture of this corcle differs at different stages ; at first it 

 consists of a thin glary fluid ; afterwards becomes 

 more concrete, regularly organised, and at last dis- 

 plays the rudiments of the radicle and of the plumule. 



The perfect seed, as has been already described, is 

 composed of cotyledons, a corcle, membranes, and ves- 

 sels. (Part I. Sect. ii. Art. 1.) Fig. 1, 2. Plate Ixvi. 

 It is retained in its proper situation by an umbilical 

 cord. If a section be made of a germinating seed, 

 a hollow channel will be observed in the cotyledons, 

 which receives the name of ditctus chylijents. It 

 comlnunicates with the rostel, and terminates in the 

 pith. This duct is supposed to convey nourishment 

 to the young plant. 



All plants are not provided with a rostel, as Willde- 

 now ascertained in the Trapa natans, but there is no 

 proof that any part can ejujf without a plumula and 



