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stoneware jars used for issue. The method of preparation finally adopted is as
follows :—Into each jar four pints of Acid are measured and after the addition
of the Acid 21/2 Ibs. of carefully powdered Perchloride of Mercury are slowly
added while the whole is being briskly stirred with a wooden rod. The Perchloride
is dissolved in a few minutes and the jar is filled up with water. The solution
thus prepared is kept for 24 hours when it is examined, and if tbe solution is clear
and there is no deposit the Méthylène Blue is added and the stopper screwed up
tightly. The jar is then labelled and set aside to await issue.
A saturated solution of Méthylène Blue is prepared by dissolving the crystals
in a mixture of acid and water. Two ounces of this solution is added to each jar.
It was found necessary to dissolve the Méthylène Blue before adding it to the
disinfectant solution as the crystals would not dissolve when added to a solution
containing Perchloride of Mercury.
The Perchloride cf Mercury is supplied in brown paper packets weighing
about "28 Ibs. each. Tests are applied to samples from each packet to ascertain
the purity or otherwise of the Perchloride supplied. The tests used are—
1. The solubility in water. It should dissolve in excess of water on
gently heating without leaving any residue.
2. When the crystals are heated in a test tube the whole should
sublime and be deposited on the cold part of the tube in the
form of a thick white powder.
3. On the addition of Iodide of Potassium to a solution of the salt in
water a red precipitate (Iodide of Mercury) should form which
re-dissolves on addition of excess of the Iodide solution.
The Perchloride supplied was very pure and in every case conformed with
the above tests, with the exception that in a few of the packets that had got damp
a small proportion of the Perchloride had been converted into the brown Carbonate
of Mercury. The amount of carbonate present in any individual packet did not
exceed a few grains in weight.
In some of the packets a few small pieces of glass were found, but practically no
adulteration was present and none of the Perchloride had been converted into the
subchloride (calomel).
The Hydrochloric Acid is supplied in stone screw stoppered jars holding 201bs.
of acid. The acid was supplied in jars of 2 kinds, i. e., with small stoppers and
with large stoppers. The acid in the first of these jars was the best in quality. In
the majority of the jars the quality of the acid was good, but 5 jars had to be
returned as they had evidently been diluted with water. In the jars containing
this diluted acid the stoppers were loose and had evidently been recently tampered
with. When the stoppers were tightly screwed on, the acid was always found to
be of full strength. No direct tests were applied to ascertain the strength of the
acid, but if the acid did not give off dense turnes when exposed to the air the
jars were rejected and returned to the contractor who replaced them with others
of full strength. The acid is syphoned out of the jars by means of a glass acid
syphon into a measured glass jug, from which it is poured into the issue jars.
Some experiments were carried out to ascertain the quantity of acid that
should be added to each jar in order to get the full effect of the germicidal action
on the Plague Bacillus. It was considered advisable to add sufficient acid to
render cowdung floors acid in reaction for a period of at least 24 hours. At first