Section II.
OP %'EGETAI}Lli(t AND ANIMALS.
Tlic numerous beiiif^ which are endoned with life and organisution, are divided, according to the pecu- liarities they exhibit, into vegetables and animals. It i& diilicult to establish a rigorous line of demarcation be* twvcn these two great classes, because they both partici- pate in many of those properties wiiich arc tlie most essential attributes of organized bodies. Tiiu», for ex- ample, every vegetable and ewry animal possesses a structure proper to itself, and %vhich is composed of fluid and solid parts intimatiJy combined together ; ii^ both cla<ises this structure is produced by generation^ developed and supported by nutrition, and destroyed hy dL-nlh. In each instance, also, the ordinary alfinities of cbi-mistT)- and the attraction of gravitation are con- trolled, and even opposed, by anotlicr force, which is called vital ; in virtue of which, every living body is enabled to resist the influence of exttruol agents, and thus to preserve its pcctdiar composition. There in yet one other class of important phenomena, by which the' resemblance livtween vegetable and animal bodies is ren-
DIFFEKBNCKH SETWRBN
dered &till more Apparent ; ! allude to those changes which succeed the loss of vitality, and which produce putrid decomposition.
The distinctivo marks of plants and animals are, liow- cvcr, numerous and decisive. Tlie foriiiur are fixed to the earth, and are incapable of producing perceptible movement : the latter exist upon the surface of the earth, and possess the capability of spontaneous and free mo- tion. Plants, although totally deprived of conscious- ness, appear to be proiided with an obscure kind of sen- sibility which fits them to receive the impression of nutri- tive particles. Animals enjoy a higher degree of sen- sibility, which bestows upon them consciousness, and by which they have the power of pcrcei-ing all external impressions, and of determining, by an act of volition, the contraction of their muscles.
Vegetables have a composition which is more com- plex than that of minerals, but less so than that of animals ; the}' are also distinguished by containing a large quantity of solid matter, and by having carbon for their base ; which circumstances explain tlicir remarkable durability and resisljmci; to putrefaction. The animal body, on the contrary, is characterised by the number and volatility of its elementary materials, by the large proportion of its fluids, by having for its base a gaseous and diffusable substance called azote, and, lastly, by the rapidity of its decomposition aAcr death.
The plienomcna which are exhibited in the process of nutrition, constitute another and a striking distinc- tion between the two great classes of organized brings. The plant absorbs the particles which are required for hs nourishment from the surrounding atmosphere, and esp«ciaUy from the soil in wliich its roots are implanted.
VEQETADLBS AND ANIMAL8. 9
every aaitnal, with the exception of a few tribes placvd at the i>uttx>m of the acali;, tlie alimentary sub- staocas arc seized hy the agency of muKculiLr contraction, and are then introduced into an internal cavity, in which a Hepiiration is effected between the nutritious and the Useless parts ; the former ore absorbed and become as- similated with the body, while the latter are discharged under the form of cxcremeut, Tiie process by which the nutritious mutter is separated from the common muss of the food, is termed digestion. ^
DIFFERENCES BETWEExV VEQETABLES AND ANtMALS.
f Ak fixed lo the eailli, have no
p(ccc|jlit)li: motion. |I[iVf probably no obscure kind
«I leiaibilKy wiibout caaaa-
OUfDOt.
^AiB coiDpoMd of few elemonlt. Inn mach tolid mttter, »nd hare ctibon Tot Ihcit buc.
fBcmt dKOmpoMtton.
'An nouttabed by uternul ub. torption.
Hove upon the tuifacc of the
mrlli. Ilavetemibtlitynccampanicdb/
CODUrlOUHIISl.
Are competed of many clrmcntt, hnve n largi; luuiilily o( fliiidi, and have aiok for llteit biiK.-.
Arc readily (laconiiioKd.
Am iioudtbeil by di|^liou and iaieiiul abiorption.