BAR 



is nevertlielcfs, Vie fays, furnifhed with lympliatlcs to abforb 

 water and nutritious juices from the earth, and is covered 

 with a moiftcned cuticle, while the bark of the llcm is fur- 

 niflied with lymphatics to abforb moilture from the air, and 

 is covered with a drier cuticle ; the latter rcfembling the ex- 

 ternal llcin of animals and the lymphatics whic!i open upon 

 it ; and the former, the mucous membi-ane of the llomach, 

 and its ladtals. ' 



The interior barks of fome trees, like the albarnum or 

 roots defcribed above, contain, he thinks, much mucilagi- 

 nous or nutritious matter ; as the bark of elm {ulmus), 

 and of holly {ihx), and probably of all thofe trees or 

 fhrubs which are armed with thorns or prickles, which are 

 dcCgned to prevent the depredntions of animals on them, 

 as the hawthorn, goofeberry, and gorfe, crataigus, rlbcs, 

 graffularia, uhx. The internal barks of thtfe vegetables 

 may, he thinks, be conceived to be their alburnum lefs indu- 

 rated, and might probably all be ufcd as food for ourfclves 

 or other animals in years of fcarcity, or for the purpofq of 

 fermentation ; as he doubts not but the inner bark of elm- 

 trees, detra£led in the fpring by being boiled in water, 

 might be converted by the addition of yeall into fmall 

 beer, as well as the alburnum of the maple and birch [iiccr 

 and betula), all wbich are now fuffered to be eaten by in- 

 fects, when thofe trees are felled. For the fugar, which is 

 extrafted from the vernal fap-juice of the maple and birch, 

 as well as that found in the manna afa (frax'mus orniis), 

 feems, he obferves, to refide during the winter montlis in 

 the root or alburnum, rather than in the bark properly fo 

 called, and to become liquefied by the warmth of the fpring, 

 or d:(rolved by the moillure abforbed from the earth and 

 conveyed to the opening b'.:ds ; but rcfides folely in the 

 roots of perennial herbaceous plants : and in the economy of 

 graffes, and he fuppofes of the fugar-cane, it is depolltcd 

 at the bottom of each joint, which is properly at the root 

 of the Item above it. 



Of the aboTe plants, continues he, the bark of the holly 

 not only yields a nutritious mucilacje, aiid thus fupplics 

 much provender to the deer and cattle in Needwood forctl, 

 by the branches cut off and Ilrewed upon the ground in le- 

 vere feafons of froll and fnow, but contains a refinous ma- 

 terial, which is obtained by boiling the bark and waftiing 

 away the other parts of it. This refinous material poffcfTcs 

 a great adhefiver.efs to feathers and other dry porous bo- 

 di::s, and has hence obtained the name of lira- linn; and 

 much refembles the cnrjutchouc or elaltic reiin brought from 

 South America, and alfo a folTil elaftic bitumen fouiid near 

 Matlock in DerbylUire, both in its elallicity and inflamma- 

 bility. Hollies may, he therefore fuppofes, be worth cul- 

 tivating for this material belldes the ufes of their wood ; as 

 the doctor was informed, that thirty years ago a perfon 

 who purehafod a wood in Yorkiliire, fold to a Dutch mer- 

 chant tlie bird-lime, prepared from the bark of the nume- 

 rous hollies, for nearly the whole fum given for the w-ood ; 

 which, if It could be hardened, might probably, lie fays, 

 be fold for the elallic refin above mentioned. Whether 

 this refembles the nutritive refinous material found in wheat 

 llower, when the mucilage and llarch are wafiitd from it, 

 might, he thinks, be alio worth inquiry. 



Other barks contain bitter, rclinous, aromatic, or acid 

 materials, which fupply the fnops of medicine, as Peruvian 

 bark, cafcarilla, cinnamon, and were defigntd by nature, he 

 fuppofes, to proteft thofe vegetables from the depredations 

 of quadrupeds or infeits. Hence, fays he, many trees, and 

 even the wood of them, after it is dried and made into do- 

 inellic furniture, is never devoured by worms, as the ma- 



BAR 



hogany, cedar, cyprefsj and hence many plants, as the fox- 

 glove {t/i^'Jtalis), hounds-tongue {j-ynoghJJfum), hen-bar.e (^V- 

 cfcynmus), and many trees, are not devoured. by any animals, 

 as then- juices would be poifonous to them, or much difagree 

 with their llomachs, if their difgullmg flavours to the nofe 

 or palate did not prevent their eating them. The fame de- 

 fence of the vegetable kingdom fruni human digeftion, ex- 

 cept thofe which have, in long proccfs of time, been feltfted 

 and cultivated, appears, he remarks, from the relation of fome 

 unfortunate fliipwrecked travellers, who have pafled fome 

 hundreds of miles along uninhabited countries almoft with- 

 out finding an efculent vegetable produdtion. 



Oth.r barks contain reftringent or colouring particles, 

 employed in the arts of dying and tanning, as that of the 

 barberry, oak, and afh [berberis, quercus, frax'mus). The 

 art of tanning confills in filling the pores of the animal 

 mucous membrane with thefe reiiringent particles found in 

 fome vegetables, which are believed to poflefs a quality of 

 fhortening animal fibres. Thus, when a long hair is im- 

 merfed fome time in a folution of the bark of oak, or of the 

 galls produced on its leaves by the punctures of infcfts, the 

 hair is faid to be fhortened. Whether this procefs be occa- 

 fionedby tile chemicalcoagulation of the mucus.of which thefe 

 fibres totally or in part confiil, or by capillary atti-aflion 

 tending to dillend thefe fibres in breadth, and thus to fnorten 

 them, as a twilled firing is fhortened by moiiture, has, he 

 fays, not yet been well invcftigated. By thus impregnating 

 the poles of animal lliins with vegetable particles they be- 

 come lefs Lable to putrefaction, as confilting cf a mixture of 

 animal and vegetable matter, as well as much better adapted 

 to many domellic or mechanical purpofes. 



The art of dying confills likewife in impregnating the 

 pores of dry fubllanccs with a folution of the colouring 

 matter extracted from vegetables Ly the capillary attractiou 

 of thefe pores to the coloured folution; and, fecondly, by a 

 chemical change of thole colouring particles after thev have 

 been imbibed, and the water of the folution exhaLd, by 

 again ttecping them in another folution, which may chemi- 

 cally alfeCt the former. Thus, fays he, as green conliRs of a 

 mixtuie of blue and yellow, it may be bell produced by boil- 

 ing the material defigned to be dyed, firll in a decoction of 

 one of thelc colours, as of indigo, and then in that of another, 

 as of the bark of barberry. And ?s a lolutiou of iron be- 

 comes black when mixed with a decoction of oak-galls, by 

 being in part precipitated ; it is probable tliat the particles 

 of this combination, of a folution of iron with rcllringent 

 matter, may be larger than either of thefe particles fepa- 

 rately ; and, therefore, tiiat if a dry porous fubllance be ini- 

 merltd, firll in a decoclioii of oak-galls, and, after being fuf- 

 fered to di-y, is then immerfed in a folution of iron, the black 

 tinge will penetrate into minuter pores, and thus becom.e 

 more inteale than if the iiibllauce had been immcrlcd in the 

 black dye already prepared. 



Other barks are, he adds, ufed for apparel, paper, cordage, 

 and for many mechanical purpofes, owing to the ftiength and 

 tenacity of their fibres, or to the finenefs of them; as hemp 

 (eiiriiialis), flax (iinuni), for the purpofes of fpinning and 

 weaving. The bark or leaves of the papyrus, a flag of the 

 Nile, was, he fays, firll uicd for paper; and the bark of the 

 midberry tree is Hill made into cloth at Otaheite, and other 

 fouthern iflands. 



The art of feparating the fibres of the bark of plants, as 

 they confiil of the caudexesof buds, or the conncdting veffels 

 between the plumules and the radicles of them, is, he 

 obfeives, performed by foaking them fome weeks in ilag- 

 naut watci", till the mucous membranes, which conneA 



thek 



