\ 



269 



Tournefort,^ and confequently not the Tragacantha of Llnnsus.' He 



diCis the opinion of Tournefort, who attributes the flowin 



/ 



of the gum to the contradion of the fibres of the bark, occafioned 

 by the intenfity of the folar heat; obferving that it is only during the 

 night, or when the fun is obfcured by clouds, that the gum iflhes 

 from the plant, and that the ilune has been remarked at Crete. 



" Gum Tragacanth differs from all other known gums, in giving - 

 thick confidence to a much larger quantity of water;* and in bein 

 much more difficukly diffoluble, or rather diffolYing only imperfedly. 

 Put into v/ater, it flowly imbibes a great quantity of the liquid, fwells 

 into a large volume, and forms a foft but not fluid mucilage : if more 

 water be added, a fluid folution maybe obtained by agitation, but the 

 '•quor looks turbid and wheyifh ; "and on ftanding the mucilage fub 



fc> 



^ «.j.i\^ iiiLi^.ixa.i' 



fides, the limpid water on the furface retaining little of the gum:"4* 

 nor does the mixture of gum arabic promote their union. 



The demulcent qualities of this gum are to be confidered as fimilar 

 to thofe of gum arabic : ' it is feldom given alone, but frequently in 

 combination with more powerful medicines, efpecially in the form of 

 troches,^ for which it is peculiarly well adapted. It gives name to 

 officinal powder, and is an ingredient in the compound powder 



of cerufs 



The 



that of Libanon is yellow j the leaves of the firft are downy, of the fecond they are 

 fmooth. The flowers of one are red, thofe of the other are of a pale yellow. From hence- 

 he infers that there are various fpecies of Aftragalus which produce gum tragacanth. 



Tra 



Multo fortius eft hoc ffummi, quam G 



Arab. unc. 8 ad eundem elFeaum prseftandum. Berg. M. M. p 



G 

 G 



d 



<^ Edin. Difpen. p, 179 



fix 



M.M, 



Obfe 



\ See p. 189. Bergius fays, Virtus: dc 

 la, Diarrbcea, Stranguria. /. c. p'. 62 



Ufi 



L-o 



\ 



FANAX QUINQUEFOLIUM 



*«• 



