Dr. Pearfon’s Experimenis on Calculi. 389 
it precipitates the fulphures; and we muft not forget that 
Scheele reprefents it as the weakeft of all acids. Why then 
fhould Dr. Pearfon, without any new facts refpecting its cha- 
ratters, with to include it among the oxyds? Are the latter 
even taken in the clafs of ternary or quaternary oxyds, vege- 
table or animal, foluble like it in alkalies; and do they fatu- 
rate them? Is this owing to its little folubility? But the 
faccharine oxyd is very foluble in water without faturating 
alkalies. Is it not manifeft, on the contrary, that it wants 
one of the principal chara¢ters of thefe complex oxyds, among 
which the French pneumatic chemiftry claffes a great num- 
ber of organic compounds? Does it not rejeét this acidifi- 
cation, fo eafy in other oxyds of the fame kind, that change 
fo rapidly into the oxalic or acetous acids by the a¢ction of 
the nitric and oxygenated muriatic acids, as Dr. Pearfon has 
fo carefully confirmed ? How came he not to perceive, that 
this difference between it and the other vegetable or animal 
oxyds required from chemifts that they fhould place it in 
another clafs of bodies; and that, too much oxygenated, no 
doubt, to pafs to a new ftate of acidity, being already itfelf 
as much fo as the nature of its compofition would admit, it 
could not but lofe its combination by the ftrong action of the 
oxygenating compounds, and pafs, as was really the cafe, to 
the laft term of animal decompofition, the ftate of a double 
binary compound ; the carbonic acid and ammonia? TI am 
even aftonifhed that Dr. Pearfon, in analyfing this body with 
that fpirit of inveftigation which he employed, was not more 
inclined than other chemifts to preferve the acid character 
to this compound, and that he was not averfe to compare it 
with oxyds, fince he found in it fo many characters oppofite 
to thofe of the known oxyds. If we mdeed take from the 
compound oxyds contained in organic bodies that character, 
fo ftriking, of becoming acid by a greater proportion of oxy- 
gen, we fhall at once efface every thing clear and precife 
which this denomination prefents to the mind, and iia 
tute at once darknefs for light. 
Cc3 All 
