[ 433 ] 



The naufeous tafte of rhubarb feems to arife from a fweet 

 combined with a bitter, and affords room to believe, that 

 it contains a faccharine matter, which probably might be 

 obtained in a feparate ftate by a 'fuitable chemical procefs. 

 Accordingly, I find the celebrated M. Sheele, a German 

 chemift, is faid lately to have fucceeded in obtaining from 

 it a fait confifting of the faccharine acid united to an earth » 

 and M. Model aflerts, that rhubarb contains this felenetic 

 matter to the amount of one-tenth of its weight. 



How imperfedl is our knowledge concerning the confti- 

 tuent parts of vegetables, and even of thofe vegetables with 

 which we are the mod familiar ! Whence it would feem 

 advifeable, in order to have their virtues entire, that we 

 (hould give them in fubftance, the form in which nature 

 prefents them, rather than in infufion or tinfture. This at 

 leaft feems evident with refpedl to tlie drug now undef 

 confideration. 



My learned Friend the Dean of Glocester, in a late 

 converfation on this fubjelt, having dropt a hint that the 

 feeds of rhubarb might probably deferve attention, I was 

 determined to try them. Accordingly Mr. Rack fa- 

 voured me with a little parcel, of the fame age as the roots 

 of the Englifli rhubarb, (viz. four years old) though not 

 the produce of tlie fame plants. 



Experiment XIV. Twelve grains of the feeds reduced to 



* powder, were given to a woman of lifcy year? of age in a glafs of 



plain water. The powder caufed a flight iiaufea, and ficknefs 



attended with gripes, and afterwards operated briflcly three times. 



Exp. XV. The fame quantity given to a miJdIe-aged man, 

 operated twice without producing thcfe fymptoms. The fame 

 pcrfon two days .ifter took twenty grains, which operated four 

 times in a gentle, cafy manner. 



Vol. III. ' F f Exp. XVI. 



