46 
MANGANI DIOXIDUM PR.llClPITATUM. 
Precipitated Maiig’auese Dioxide. 
To replace Alangani Dioxiclum, U. S. Pharmacopoeia, 1890. It con- 
sists chiefl}" of manganese dioxide (MnOg), with small amounts of 
other oxides of manganese, corresponding to not less than 80 per cent 
of manganese dioxide. The Alangani Dioxidum (1890) was the native 
crude manganese dioxide and was onl}^ required to contain at least 66 
per cent of the pure dioxide. 
Dose. — ‘‘Average dose: 0.250 Gm. = 250 milligrammes (4 grains).” 
(U. S. P.) 
MANGANI HYPOPHOSPHIS. 
Mang“aiiese Hypophospliite. 
Mii(PHA)2 + H,0 
It should contain not less than 97 per cent of pure manganese 
hypophospliite. 
Dose. — “Average dose: 0.200 Gm. = 200 milligrammes (3 grains).” 
(U. S. P.) 
It is contained in Syampus Hypophosphitum Compositus. 
METHYLTHIONIN.P HYDROCHLORIDUM. 
Metliyltliioiiine Hydrochloride. 
Methylene Blue. 
CuIIibNsSCI 
Chemically, it is tetramethylthionine hydrochloride. 
Properties. — Dark, green, ciwstalline powder, or prismatic crystals 
having a bronze-like luster. 
Ileadil}^ soluble in water, somewhat less so in alcohol; the solutions 
are of a deep blue color. 
Incompatible with potassium iodide. Reducing agents decolorize it. 
Dose. — “Average dose: 0.250 Gm. = 250 milligrammes (4 grains).” 
(U. S. P.) 
Caution. — Not to be confounded with commercial methylene blue, 
which is often the zinc chloride double salt of tetramethjdthionine, is 
employed as a dye or stain, and is unfit for internal administration. 
Alethylene azure, a dye which has recentl}^ come into prominence as 
a stain in histology (Romanowsky’s stain, for example, depends upon 
the methylene azure present in “ripened” methydene blue), is derived 
from methydene blue by the addition of two atoms of oxy^gen to the 
sulphur. 
N 
-Ccjllg^^ 
N(CH3), 
N(CH3),C1 
I 
N 
>80^ 
■N(CH3)3 
N(CH3),C1 
Methylene blue 
Methylene azure (chloride) 
