Obfervaiions on Vegetable "Exlra&s. 385 



Canals in the neighbourhood of Damietta, and which could 

 not bear to have iheir roots innnerfed in earth moiftened by- 

 water lefs frefli than before, have difappeared ; fo that the 

 papvrus, which was very abundant in that diilrict, is now 

 exceedingly rare. The papyrus has abandoned its native 

 country. 



Inftead of this lift, it would be more advantageous to be 

 able to prefent an exact analyfis of each pharmaceutic ex- 

 tract in particular. This would be the means of enlightening 

 the apothecary in regard to their preparation, and the phyfi- 

 .cian in regard to their virtue; but the labours of modern che- 

 mifts on this point are ftill very deficient, and the antient phar- 

 macopolifts never thought of undertaking this object, which 

 they would not have been able to accomplifh with the necef- 

 fary chemical knowledge. For want of better materials, they 

 collected very juft observations; fo that, guided by them, and 

 authorized bv the example of nature, which in refinous gums, 

 fap, and relins, prefented them with products very fimilar 

 to the different extracts, they arranged the latter into four 

 claffes : 



ift, Gummy extracts. They refemble glue and jelly, and 

 are furnifhed by the'feeds of the flag, mallows, &c. 



2d, Gummy refinous extracts. Thefe are thofe which 

 contain gum and refin united together. They are obtained 

 from jalap, aloes, &c. 



3d, Saponaceous extracts. Thefe are thofe in which the 

 gummy and refinous principles are fo well combined that 

 they do not feparate. Of this kind are extracts of the car- 

 duus-benedictus, fumitory, &c. 



4th, Refinous extracts. Thefe are the refins properly 

 called, obtained either by means of alcohol, which gives 

 them more or lefs pure, or by means of ether, which fur- 

 nifhes them abfolutely freed from gummy principle. 



The different extracts have received different names. 



Robe, J'apa, defrutum,) jelly ^ extraSl. 



Robe is the juice of any fruit infpiffated to the confiftence 

 of honey. 



Sapa is the juice of grapes evaporated to the fame degree. 



Defrutum is the fame juice deprived of two-thirds of its 

 humidity, and which being left to ferment in this ltat? gives 

 baked wine. 



Jelly is the infufion or decoction of the mucilaginous fub- 

 ftances of vegetables, or the gelatinous parts of animals con- 

 centrated to the proper degree. 



Extratt is the product of the evaporation of vegetable 

 iuices, infufions, or decoctions. 



Vol. XIII. No. 52, Bb As 



