Langenhan—The Arsenical Solutions. 
165 
pure potassium salt, which, in all probability it was not. In as 
much as it is impossible to establish the purity of the potassium 
carbonate used in the original formula, it would be vain to attempt 
to duplicate, in this respect, the original formula. 
It might be argued that the “white arsenic” of Fowler’s days 
was not as pure as the present pharmacopoeial product is supposed 
to be, and that the impurities in both ingredients compensated 
each other. However, it is scarcely to be assumed that the “white 
arsenic” or arsenic trioxide was ever as impure as the potassium 
carbonate made from wood ashes, unless it was wilfully adulter¬ 
ated. (For table of ratios see Number 12.) 
8. ) Water . According to his original formula, Fowler de¬ 
manded “distilled well water”. This is probably the reason why 
distilled water has always been demanded by the U. S. P. 75 A per¬ 
manently hard water might be considered as interfering with the 
desired alkalinity of the finished product. 76 
9. ) Amount of Water Used to Effect Solution. According to 
Fowler’s original formula only “a half pound” of water, neces¬ 
sary for the finished preparation, was used to effect the solution. 
The London Pharmacopoeia of 1809, also the U. S. P. of 1820 di¬ 
rected “one pint” to be used, the loss resulting from evaporation 
to be made up. So did both editions of 1830. The edition of 1840 
reduced the amount to “twelve fluid-ounces”, as did the editions 
of 1850, 1860 and 1870. In the 1880 edition, the amount was re¬ 
duced much more, namely to one-tenth of the volume of the finished 
product. Practically the same ratio obtained in the editions of 
1890, 1900 and 1910. The London Pharmacopoeia throughout 
made no reduction. However, the first British Pharmacopoeia in 
1864 reduced the amount, prescribing 10 ounces to be used, like¬ 
wise the edition of 1885. The 1898 edition directed either 10 
ounces or 500 cc., depending upon whether the metric formula or 
the apothecaries formula was used as both were given in this edi¬ 
tion. The 1914 edition prescribes 500 cc. In all B. P. formulas 
the amount of water directed to be used to effect solution is equal 
to one-half of the volume of the finished product. 
75 The several editions of the London and British pharmacopoeias, also the 
recent editions of all other pharmacopoeias consulted demand distilled water. 
76 Such a water, which, however, no pharmacist would think of using, is the 
public spring water of Sheboygan, Wis. It contains per liter 0.2394 Mg. equiv. 
1.358 K^COg, and 1.0832 Ca. equiv. 3.448 K^COg, or a total of 4.806 K 2 C0 3 . Hence 
of the 13.804 KgCOg = 20.000 KHC0 3 used, about 9.000 K 2 C0 3 remain for the 
solution of the 10 gm. As 2 O s and the desired surplus alkalinity. 
