3St} sthcctuhe and uses of the splses-. 



5;=; cfTects oti Half an ounce of tincture of rhubarb, diluted in 1| ounce 

 of water, taken in the interTal between meals, did not pass 

 off by urine ift less than an hour, and even then was not in 

 suflicient quantity to be discovered, till the test was ap- 

 plied. 



The same quantity was taken immt'diately before a break- 

 fast consisting of tea. In 17 rainutes, half an ounce of urine 

 was voided, which when tested had a light tinge. In 30 

 minutes another half ounce was made, in which tne tinge 

 was stronger ; and in 41 minutes a third half ounce was made, 

 in which it was yery deep. In an hour and ten minutes 7 

 ounces were voided, in which the tinge of rhubarb was very 

 -weak, and in two hours twelve ounces were voided, in which 

 it was hardly perceptible. 



i.n<\ feces. In 6f hours the rhubarb acted on the bowels, and gave a 



decided tinge to the feeces; the urine made at the same time 

 had a much stronger tinge, than what was voided at one 

 hour and ten minutes. 



Gets into the I" this experiment, the rhubarb appeared to have escaped 



nnne by two from the cardiac portion of the stomach; and in two hours 



c'lHereat chau- 



;-,ei.3. ceased to pass through thatcuannel; but was afterwards 



carried into the system from the intestines, and again ap- 

 peared in the urine. 

 Fxperiment re- This experiment was repeated on another person; the 

 uiliir esulV ^^"^^'^''^ "^^23 detected in the urine in 20 liiinutes. In 2 hours 

 the tinge became very faint; in 5 hours-it was scarcely per- 

 ceptible ; in seven hours the rhubarb acted on the bowels; 

 and the urine made after that period became again as highly 

 tinged as at first. 

 PriK^iate of It was Suggested by a chemical friend, that the prussiate of 



'^^ suggest potash might be a better substance than rhubarb, for the pre- 

 sent experiments, since the solution of one quarter of a grain 

 in two ounces of water becomes cf a blue colour on the ad.. 

 dition of the acidulous muriate of iron. 

 Not to be de- To determine this point, one quarter of a grain was dis» 

 ?ected in the solved in two ounces of serum, but no blue colour was pro- 

 quantities. " duced by the addition of the teat, nor did this efifect take 

 place till the quantity of the prussiate was increased to a 

 grain; so that minute quantities of the prussiate of potash, 

 or at least of the prussic acid, may exist in the bioodj with« 

 out beincr detected by adding solution of iron. 



Thft 



