Langenhan—The Arsenical Solutions. 185 
Two factors influence the variations mentioned above: firstly, 
the variation in the As 2 0 3 equivalent of N/10 I. V. S. due to 
changes in atomic weights, and secondly, the purity rubric of the 
arsenic trioxide. The Cc. equivalent for 1880 was 0.004945; for 
1890, 0.004942; for 1900, 0.004911; and for 1910 it is 0.004948. The 
purity rubric for arsenic trioxide for 1880 was 97 p. c. As 2 0 3 ; for 
1890, 98.8 p. c. As 2 0 3 ; for 1900, 99.8 p. c. As 2 0 3 and for 1910 it is 
99.8 p. c. As 2 0 3 . 
In as much as only one gram of arsenic trioxide is used to pre¬ 
pare 100 grams of the solution, it becomes quite apparent that any 
solution assaying 1 p. c. As 2 0 3 , (the generally accepted U. S. P. 
requirement) would result only from carelessness in weighing, un¬ 
less it be that the U. S. P. formula were ignord and the equivalent 
of 10 gm. of 100 p. c. pure arsenic trioxide were used, or that a 100 
p. c. arsenic trioxide were used. 
16.) Bose. The 1900 revision of the U. S. P. is the first one to 
include the dose. This is given as “ average dose—0.2 C. (3 
minims)”. The 1910 revision likewise contains the dose given as 
“average dose—Metric, 0.2 mils—Apothecaries, 3 minims”. 
“ Doses were introduced into the Pharmacopoeia to meet a popu¬ 
lar demand—mainly to add to the value of the book to the young 
physician, but also to serve as an authoritative statement for the 
benefit of the dispenser, of the ordinary practice of the physicians 
in prescribing different remedies”. 110 The subject of the introduc¬ 
tion of doses into the Pharmacopoeia evidently called forth some 
little discussion, as to whether a maximum, a minimum, or an aver¬ 
age dose should be designated. The objection to establishing a 
definite dose was the possibility of legal difficulties if this dose were 
overprescribed. * 111 In reviewing the method in vogue for desig¬ 
nating doses in foreign pharmacopoeias, the question of overpre¬ 
scribing and thereby ignoring the standard has apparently been 
overlooked, or considered unimportant. Or the revisors of the 
pharmacopoeias had not unlimited confidence in the prescribers 
knowledge of drugs and medicines, as to place no restrictions what¬ 
soever on the quantity he may prescribe, for out of ten of the more 
recent revisions of foreign pharmacopoeias consulted, seven give a 
maximum dose. Three give no dose, but state that the solution 
must be dispensed with caution (or its equivalent). Not only is 
110 Lyons, Cir. of the Comm, of Revision of U. S. P. VIII, Cir. 447, p. 1934. 
111 Remington, Ibidem, Cir. 447, p. 1821. 
