146 Wisconsin Academy of Sciences, Arts, and Letters. 
C. Action of Hydrogen Chloride on Arsenous Acid. 
For the present purposes the diarsenous acids and other more 
or less complicated possibilities may be disregarded. Taking into 
consideration only the simple meta and orthoarsenous acids, the 
possibilities are indicated by the following structural formulas: 
/OH /OH /OH ^C1 
As—OH As—OH As—Cl As—Cl 
\OH \C1 \C1 \C1 
^O 5^0 
As—OH As—Cl 
Again it becomes apparent that when arsenic trioxide is dis¬ 
solved in water with the aid of hydrogen chloride, a number of 
products, rather than a single one, are likely to result and that the 
equilibrium, that finds its expression in a given pharmacopoeial 
preparation, will depend on a number of factors. 
LIQUOR POTASSII ARSENITIS (FOWLER’S SOLUTION). 
History : —The arsenicum album 17 of the alcemists, the arsenous 
acid of the antiphlogistic nomenclature, our arsenic trioxide, ap¬ 
pears first to be mentioned in the Latin alchemistic manuscripts 
formerly attributed to Geber. 18 Under the ban of the phlogistic 
theory, it was regarded as the calx of the regulinic arsenic, a half 
metal (Brandt, 1733). 19 This conception paved the way to the 
recognition of the “white arsenic” as an oxide of the element. 20 
The differentation of the two oxides as acide arsenieux and acide 
arsenique in accordance with the new nomenclature of Morveau, 
Lavoisier, Berethollet and Fourcroy (1787) naturally followed. 
The recognition of the several arsenous acids: ortho, meta and 
pyro and their several salts also of the isomeric trioxides came 
later. 
17 So called to contrast it with arsenicum citrinum (auripigment) and arseni- 
cum rubrum (realgar), Kopp, Geschichte der Chemie, vol. 4, p. 90. 
18 Kopp, Geschichte der Chemie, vol. 4, p. 90 ; also E. v. Meyer, History of 
Chemistry (3rd ed.) p. 58. 
1# Kopp, Geschichte der Chemie, vol. 4, p. 92. 
“Kopp, Geschichte der Chemie, vol. 4, p. 99. 
