122 On the alkaline Matter contained in dropsical Fluids 



P.S. — I must say this, that I think the Gentlemen of the 

 Society of Aris. he. are very unhandsonielv treated by the 

 critic to whom I have alkuled, as if they exercised no judge- 

 ment on whom, or for what, they bestow their honourable 

 and bountiful rewards. 



XIX. ^n Jnswer to the Ohservatious of Dr. Pearson {see 

 our last Number) on certain Statements respecting the 

 alkaline Matter contained in dropsical Fluids, and in 

 the Serum of the Blood. By Alkx. Marcet, iV/.D. 

 F.R.S. one if the Physicians to Guy's Hospital, 



To Mr. Tilloch. 



SiK, Although I feel disinclined to engage in any public 

 philosophical controversy, especially when the object is to 

 vindicate statements, the truth of which any common ob- 

 server may easily ascertain by experiment; yet, as there are 

 some points in the above communication which do not 

 place the question in ils proper light, and might mislead 

 those who have no opportunity of referring to the original 

 documenis, I have thought it necessary to offer in return 

 a few observations. The state of the question is simply 

 this : all chemists have for a long time agreed that the 

 blood, and probablv all the animal fluids, contain, together 

 with various neutral salts, a certain portion of alkali not 

 combined with any acid. This alkali has generally been 

 considered as being soda, although a few chemists had also 

 noticed traces of potash in some of these fluids. Dr. Pear- 

 son, on the contrtiry, in examining various kinds of animal 

 substances, and especially of expectorated matter, was led 

 lo conclude that the whole of the uncombined alkali con- 

 tained in the animal fluids, was potash ; and that they did 

 not contain uncombmed* soda in any proportion what- 

 ever. 



In analysing the fluids of dropsy, I vi-as naturally led to 

 inquire into this question, and the results obtained induced 

 me to conclude, that the only uncombined alkali present in 

 the blood, or other animal fluids, was soda; and that the 

 indications of potash, which by applying the test used by 

 Dr. Pearson I was able to delect in these fluids, were owing 

 to the presence of that alkali in a state of combination 

 with the nuiriatic acid. 



The experiments I adduced in evidence were of two 



* By the expression uuQvibined, I mean not combined %\'ith acid. 



kinds} 



