[ 446 ] 



L E T T E R VI. 

 [From Mr. R. C. Sims, Dunmow, Eflex.] 



^'^0 inveftigate the medical properties and powers of 

 rhubarb of Engli(h growth, and to determine the 

 proportion of its ftrength to tliat of the Turkey and Eaft- 

 Indian fort, with any degree of accuracy, is a nice and dif- 

 ficuh point. It requires the confideration of the differ- 

 ences which may occur in the fpccimens themfelves, in the 

 conilitution and prefent (late of the ftomach and bowels 

 of the i^erfons taking it, and in the feafon, and other inci- 

 dental caufes of difference. Many of thefe circumftances 

 are obfcure enough to efoape or baffle the obfervatioti of a 

 diligent enquirer; and yet fo efficacious in changing and 

 determining the medical powers of a medicine, as to caufe 

 the fame drug to produce very different effects in different 

 pcrfons, or even in the fame perfon on different trials ; and 

 at another time to caufe two drugs, of different medical 

 powers, to produce effc.ts nearly fimilar: therefore nothing 

 lefs than a variety of different trials, repeated by different 

 perfons for a length of time, can ellablirti certainty in this 

 cafe. It would be wrong to amufe with crude experiments. 

 Therefore all I can now fay is, that the fample No. I. ap- 

 pears the bed of the two, and to refemble the foreign in 

 colour, flavour, and grain, more than No. II. 



Both famples ccnfift of a larger and a fmaller piece: 

 the larger cut flat, and the fmaller cylindrical, or a frag- 

 ment. A drachm of each piece, and of Turkey, and good 

 Eaft-Indian rhubarb, each frefh powdered, and placed on 

 a feparate piece of paper, ranged, when compared with 

 refpeil to deepnefs of colour, in the following order: iff. 

 The flat piece of No. II. by far the paleft. 2d, The cy- 

 lindrical 



