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LIV. Reply to a Letter of Dr. Marcet to Dr. Bostock, 



on the Subject of the Mkali in the Animal Fluids. By 

 George Pearson, M.D.F.R.S., ^c. 



To Mr. Tilloch. 



George-Street, Hanover-Square, 

 J October 'J7, 1812. 



Sir, In your Journal for the preceding month I read the 

 letter of Dr. Marcet addressed to his friend Dr. Bostock, in 

 which he offers the evidence of some experiments to prove 

 that the potash which exists in the animal fluids is in the state 

 of muriat (muriate), and that the whole of the uncombmed 

 alkali is soda. It appears that Dr. Bostock was of opinion 

 that the siipjiosed uncombined alkali was potash, as 1 pro- 

 visionally concluded, and not soda j but on the representa- 

 tion of evidence just mentioned, he has changed his opi- 

 nion ; and therefore has become the vehicle of Dr. Marcet s 

 letter to the public, confiding, he says, that you Mr. Editor 

 will assent that the experiments stated '' must entirely set 

 the question at rest." One authority declarinfi the question 

 to be entirely set at rest, and the other (the author) affirming 

 that every shadow of doubt is now removed, although I 

 was not ready to believe, as 1 have had occasion to assert, 

 that more than provisional conclusions are likely to he ob- 

 tained, 1 at least expected to find some new contravening 

 testimony. This I was prepared to acknowledge; tor, rea- 

 soning merclv from the known facts, I should have felt no 

 humiliation if new evidence indicated adverse conclusions : 

 A"o5 non judicis sed indicis personam sustincmus. (F. Bacon.) 

 But ou examining the evidence which it is asserted has 

 produced conviction, "removed every shadow of doubt, 

 and '* set the question at rest," I was unable to perceive 

 any new facts to alter mv former conclusions. Hence, I 

 might have replied merely by a counter declaration, and 

 tefeience to my unanswered experiments and inferencts. 

 As however this mode of procedure may be deemed neither 

 decorous to my opponent and the testimony produced of 

 respectable personal authority, nor satisfactory to the public, 

 I respectfully offer the following brief exposition and re- 

 maikg. The pucess which Dr.^Marcet says authorises his 

 confidence was this : 



The saline niattwr* of the serum of blood vvcre procured 



by » vapopiHin to dryness, incmeration, dissolution in v^a- 



ter, fillralioii, t-vaporan' ii .is;ain 'o drynes:.:, dissolutioo in 



^etic at id, dissolution a'/am of the desiccated acetic com- 



Vol. 40. Nv. I7i. iVo//. ibi2. X pound 



