AM) WHAT TIIKV Ixi. 



87 



1 



or colls (Hvidod f)fT by wholo partitions ; iiml to rise nti inch tln^ sap /^'cncrjilly 

 lias to ))ass tliro(i<;h scvcial luniiljcd siicii jtaititiotis. W'lnii tln-ic is imicli 

 woOil, tho sap rises mostly tlinm^'li that. Now Ihr lihrrs ami the vessels ol' the 

 \\o:y\ are tnhes, most of them several times jini^ifr than wide ; lait their ends do 

 not open into each othei' ; a closed pai'tition divides each cavity tVom the next, 

 Wi:ich tlie sap has to <:et throujLrh somt' way or othei-, Ijou it ;L'cts (hnni^di so 

 readily, we do not alto;,'ethei' know; hut there is no doid»t. al»out the tact. 



261S. ('arri«'d into the le.tves, iind distributed thron^di theii- l»road snrhice, tln> 

 crude sap is exposed to the linrht and air. .\ lar<;e part ot' it is water ; ami 

 each di'op of this serves to brin;,' uj) a minut<' portion of eai'thy matter, which 

 it dissolved out of the soil. Most of the water, no lonijer wanted, is evaporated 

 from the leaves by tlu; wai-mth of the sun, and ixli'ihil ,• that is, it esoajies iti 

 vapour into tlu^ air, mostly through the bi-eathing-pores (264 \ What remains, 

 tlu' plant is at the same time 



269. Digesting or Assimilating. Assimilating is the projier word. To assimilato 

 is to nndce similar, or to tin-n into its own substance. This is just what ))Iants 

 do in their leaves. They change into vegetable matter that which was mineral 

 matter (air, earth, or water) before. This they do only in (he Icives. or other 

 ^reen j)arts, and in the.se otdy when the}' are exposed to the ligiit of day, that is, 

 to the influence of the sun. W'e see, therefore, why ))lants ai-e so dejiendent u\\ 

 the light. They cannot grow without it, except so far as they are fe<l l»y vege- 

 table matter prepai-ed beforehand ; —as the seedling is feil at the beginning, by 

 vegetable matter of the parent plant stored up in the seed (Chaj). IF. Sect. 2); 

 and potato-shoots, by that provided in the tuber or potato (74, 75), Ac. This 

 enables them to begin their growth in tho dark. But the inheritance only serves 

 to set up the young plants ; when they have exhausted it, they ha\<' to work for 

 themselves, to take in air and water, and a little earth, and ((.^-^iuu'/dfr it, /.'., 

 make vegetable matter of it, — in their leaves or other green parts, with tho 

 help of sunshine. This they do throughout the whole growing season. 



270. 1'he new-made vegetable matter is dissolve 1 in the water or the sap in 

 the leaf, and forms a thin mucilage. This is prepaied or Khihorat'il Sti/i, fit to 

 be used in growth ; for it contains the sume material as tha^ which tlui ])lant 

 itself is built of. It is to the plant just what the prepared cl:'y is to the earthen 

 vessel, or t( the bricks of which the house is built. It has only to be conveyed 

 where it is wanted and used for growing. 



