TJ3B Mr. Phillips's Reply to Dr, Christison. [Nov. 



is to account for your having months previously made two blun- 

 ders on another. 



But to facts. — I deny that I have used the vy^ords mix and digest 

 ambiguously. Alluding in my first paper to the use of animal 

 charcoal, my words are, " I, therefore, mixed some of it with a 

 coloured solution of arsenious acid, &c. ; and afterwards suppos- 

 ing it might be suspected that the phosphate of hme of the 

 animal charcoal might have produced by its solution an appear- 

 ance of the presence of arsenious acid, I state that " I found, 

 however, that water or wine which was merely digested on the 

 animal charcoal produced no effect with nitrate of silver, &c.'* 

 Now, Sir, observe the charcoal was mixed with arsenical fluid, 

 and only mixed, that the arsenious acid might not be separated 

 by it. The animal charcoal was digested in water and wine, in 

 order to dissolve the phosphate of lime if possible. Had you 

 quoted this passage, you would not have ventured to assert that 

 1 had directed animal charcoal to be digested in a fluid contain- 

 ing arsenious acid, for none was present, and the object ia 

 digesting was totally different. 



Again, you represent me as having employed a decolorized 

 solution containing a grain of arsenious acid per ounce, when I 

 have distinctly stated that " the silver test readily detected the 

 arsenic when so far diluted as to form only - Yolab ' °^ ^^^ solu- 

 tion." Nor is this all : you insinuate that I could not distinguish 

 between the green colour produced by adventitious matter from 

 that obtained by the combination of arsenious acid and oxide of 

 copper; but if you had attended to the precaution which I 

 recommend of first precipitating the hydrate of copper, and then 

 adding the solution of arsenic, you would, I think, have seen 

 that I could not have made this mistake. 



1 have already admitted my error in supposing that I had used 

 a precaution which I did not employ ; an imperfect recollection 

 of what I had written is, however, a mistake which I trust you 

 will be inchned readily to pardon, for it is one into which you 

 have yourself fallen. You say in your reply, that with respect to 

 authors who treat of medical jurisprudence, you *' unfortunately 

 wrote most authors instead ot some authors." The construction 

 of your sentence is such, however, as to show that the error was 

 of a more deliberate nature, and not a mere slip of the pen. 

 You " unfortunately," for the latter supposition, wrote *' almost 

 all authors." 



In my remarks upon your paper, I have noticed your assertion, 

 that "the charcoal of the black flux is not necessary in the 

 process [of reduction], and subcarbonate of potash might, 

 therefore, answer as well, but it is seldom so dry." 



In your reply, you say, " I meant the process in the text, — 

 the process for reducing the sulphuret ; and I distinctly remem- 

 ber that my reason for introducing the clause was, that if I did 



