PRINCIPLES OF VEGETATION. 341 



the cafe where trees of a fimilar nature are united, and in thofe where . 

 curiofity has combiried difiimilar natures, it has been partly the cafe ; the 

 nutriment has been in a degree forwarded toward fitnefs, and the graft has 

 completed its deficiency. That juices thus iW\cq Jirained, as it were, firft 

 by the roots of the tree, then by the pores of the graft, fhould gain or iofc 

 fomewhat alterative to the flavour of the fruit yielded by the graft, is not 

 wonderful; that it (hould be enriched or mellowed, fhould be acidulated 

 or foftened, feems natural, and to depend on the qualities of the tree 

 from which it now derives its nourifhment. 



But as the general propagation of vegetables is rather by feeds than by 

 any other mode, to them we fhall now turn our attention. 



Seeds of plants are of various figures and fizes. Moft are divided into 

 two lobesi though fome, as thofe of the crefs-kind, have fix j and others, 

 as the grains of corn, are entire. 



But as the effential properties of all feeds are the fame, when confi- 

 dered with regard to the principles of vegetation, our defcription fhall 

 be limited to one, the great garden-bean j becaufe, after it begins to 

 vegetate, its parts are more confpicuous than many others, and confe- 

 quently better calculated for invefligation. 



This feed is covered with two coats or membranes; the outer ex- 

 tremely thin and full of pores, but may be eafily feparated from the inner 

 one (which is much thicker), after the bean has been boiled, or lain a few 

 days in the foil. At the thick end of the bean is a fmall hole vifible to 

 the naked eye, immediately over the radicle or future root, that it may 

 have a free pafTage into the foil. When thefe coats are taken ofF, the 

 body of the feed appears, which is divided into two fmooth portions or 

 lobes. The fmoothnefs of the lobes is owing to a thin film or cuticle 

 with which they are covered. 



At the bafis of the bean is placed the radicle or future root, whofe 

 trunk, juft as it enters into the body of the feed, divides into two capital 

 branches, one to each lobe, and fends off fmaller ones in all diredions 

 through the whole fubflance of the lobes : thefe become fo extremely mi- 

 nute toward the edges of the lobes, that they require the fineft glafles to 

 render them vifible. To this Grew and Malpighius have given the name 

 o{ feminal root; becaufe, by means of it, the radicle and plume, before 

 they are expanded, derive their principal nourifhment. 



The plume, bud, or germ, is cncloled in two fmall correfponding ca- 

 vities in each lobe. Its colour and confiftence is much the fame with 

 <fcofe of the radicle, of which it is only a continuation 3 but having a quite 

 . Part VI. No. 31. 3M contrary 



