AND WHAT TIIKV l)l>. 



89 



circulation of tho two kinds of sap; and no <'iii»lo sap exist.** s«>paratoly in any 

 pnrt (jf tli»» plant. Mven in tin' root, wlicrc it rnt»M's, this Miinj;l»'s at oncp with 

 Honif ('lahorat«'(l sap aUvady tlu'rt', and as it risi's throu;;h th«' stiMu thry mix 

 nioi'p and more. lint whatrver is not assiniilatrd nnist h<*, Itctorc th<> plant 

 can us»' it ; that which has Ihmmi assimilated, can h«» used whci«'v«'r it may he. 



274. The claltoratcd sap, like tin* cnidc, is contained in the caxities, cells, or 

 slioi't closed tnltes which makeup tne l"al»ric(»t" the |. hint, and circulates or passes 

 from one to another throu^di th«? partitions. How it passes throu;:li. ami what 

 attracts it wher«» it is wanted, we do not very well know. And what we do 

 know could not l)e well explained to the youn<; he;;inncr, for whom this hook is 

 written. The same may lie said ahout 



275. GrOWlll. (Jrowth is the increase of a li\iu;; tliin;; in si/e ami suhstancp. 

 In plants it is done hy the incroase in the rnimhei- of the rrllft (or cavities di\ ided 

 oil l>y partitions) which make up the faluic, and hy the increa.se of »'acli in si/e to 

 n cert.'iin (i.xtent. That is, growth is the laiildin;,' up of the plant, or of additions 

 to it, out of vej,'etal)l(f matter. And this ve<,M'tahle matter was made in the leaves 

 (either of the .same plant or of its pareni ), out of mineral matter drawn from the 

 earth and the air, — was mostly made of air and water. Tor the earthy part 

 which is left hehind when we hurn a jdant (and so turn all the ve^'etahle matter 

 back into air and vapour of water a;;ain) forms oidy a Ncry small part of its hulk. 



276. if th;* pupil would learn more particidarly how ^'rowth takes place, and 

 how ])lants chan<re mineral into ve<,'etahle matter, they nnist study three or four 

 lessons of the liessons in iiotany already refj'i'red to. iJut our short and simple 

 accf)unt of the j)lant in action, /.r., inji-tutuKj, is suHicient for answerin<^ the main 

 question, viz. : — 



277. What Plants do. ^''-H'^fafion consists essentially of two thiufjs, namely, nn' 

 similatiiiii ixm\ <ii(.'itih. In a.ssimilation plants jire chan<rin^' mineral m.atter- — ^air, 

 water, and a little earth — into ve<;etal)le matter; and in <i;i-owtti this ve^etahlo 

 matter is \vroujn;lit into all manmu- of heautlful and u.seful forms. This is the 

 work which the vast variety and infinite numherof plants over all the earth are 

 busily en<?a«jed in. It is tltrlr jy^'ufidr irork ; for only plants can live upon (or 

 assimilate) mineral matter ; they only have the power of changing air, water, 

 and eaith into organic matter. 



278. What is the effect of this action of plants, especially upon the air we 

 breathe ? And what becomes of all the vast amount of vegetable matter which 





