782 
II. EN DEM ANN. 
By referring - to this table it is easily understood that sample 
No. 2, hydi ozone, is far superior to any other brand which 
has ever been made, not only on accoun, of its containing a 
much larger amount of available oxygen, but also owing to the 
presence of a small quantity of several essential oils, the respec¬ 
tive nature of which could not be determined, very likely because 
they have been submitted to the oxidizing action of peroxide of 
hydrogen before being used to make “ hydrozone.” 
I attribute to this small quantity of essential oils the great 
superiority of hydrozone over any other brands of H2 O2 as a 
healing agent. 
When hvdrozone is diluted with distilled water, in the pro¬ 
portion of half and half, the resulting mixture contains about 
13.5 volumes of available oxygen, and its bactericide power still 
remains the same as the bactericide power of sample No. 5, 
which contains 16.55 volumes of available oxygen 
Sample No. 14 comes next to sample No. 5, but it is readily 
seen that the degree of acidity is entirely too large for a prepa¬ 
ration which is to be applied to the most sensitive diseased 
mucous membranes. 
Sample No. 11, called “ Pyrozone,” which contains 11.20 
volumes of available oxygen, is quite similar to sample No. 6, 
with the exception that the latter contains a small quantity of 
salicylic acid. Very likely the salicylic acid has for its object 
to increase the bactericide power, but, unfortunately, I fear that 
it impaiis the keeping properties of this preparation. 
Acidity. 1 he fourteen brands which I have examined con¬ 
tain free acids (phosphoric, sulphuric, muriatic), and I must say 
that peroxide of hydrogen medicinal should never be made 
neutral before using, even in the most delicate cases. Neutral 
peroxide of hydrogen rapidly decomposes under all conditions 
of exposure. 
1 he keeping properties of H2 O2 solutions vary a great deal 
with the degree of purity and the percentage of free acids con¬ 
tained therein. 
li the proportion of acid is too large, the profession well 
