CHEMICAL DISINFECTANTS. 
45 
the caustic alkalies and alkaline earths decompose organic 
matter with the evolution of ammonia, which by oxidation 
may become converted into nitric acid. Woodwork or stone- 
floors. to which a coating of limewash cannot be applied, 
requires only to be washed with caustic soda or soft soap, to 
obtain an effect identical with that which lime occasions. 
(( 2. Nitric Acid seems latterly to have fallen into disrepute, 
but certainly undeservedly. It acts more rapidly on many 
organic compounds than chlorine does, attacking their carbon 
as well as their hydrogen, and as it is not required in large 
quantity its application is not costly. 
“3. Chlorine . — Of chlorine, which is at present the favorite 
disinfectant, it is needless to speak. Its peculiar power of 
decomposing combinations of hydrogen gives it, in one 
respect, a superiority over nitric acid, which does not decom- 
pose many of the gaseous hydro-carbons ; but it should not 
be forgotten that it is only in the presence of light that this 
action of chlorine is fully displayed, so that its disinfectant 
influence is comparatively small in the case of dark or ill- 
lighted apartments, such as underground cellars, the lower 
cabins, or the hold of a ship, which are the very places where 
disinfectants are often most wanted. 
“ 4. Aqua Begia , as uniting the properties of nitric acid and 
of chlorine ; each of which has peculiar virtues, the former 
in particular being a powerful oxidising agent, the latter 
possessed of great decomposing action over hydro-carbons, 
appears entitled to a high place among disinfectants. It can 
be cheaply procured by pouring oil of vitriol on a mixture 
of nitre and common salt, or by heating a mixture of nitric 
and muriatic acids. 
“ One of the most rapid and effectual methods of dis- 
infecting a large empty apartment, such as an hospital w ard, 
would be to place in one corner a vessel containing the 
materials for chlorine, such as oxide of manganese and 
hydrochloric acid, or oxide of manganese, common salt, and 
oil of vitriol; and in another corner, a vessel containing 
nitric acid and a few fragments of copper, so as to evolve 
nitric oxide, which would spread through the apartment and 
form nitrous acid there, oxidising everything oxidable which 
it contained, whilst the chlorine specially attacked the hydro- 
genous compounds. The walls might then, if necessary, be 
lime-washed, with a view alike to destroy any adhering 
organic matter which had resisted the action of the gases, 
and to neutralise any traces of free acid. 
ei 5. The last of the disinfectants proper to w r hich I refer 
is the singular substance ozone, which has a special interest, 
