LIQUOR POTASSÆ—POTASSA FUSA, or _Kali Causticum_—_Lapis
Infernalis_—_Causticum commune acerrimum_. POTASSA CUM CALCE—POTASSÆ
SUB-CARBONAS, or _Salt of Tartar_—_Potash_—_Pearl ash_.
Potass is rarely met with in a pure form, except in the laboratory of
the philosophical chemist, and is therefore not likely to become an
object of judicial enquiry; but in various states of mixture, as
presented in the different preparations above enumerated, it may become
the accidental, as well as criminal means of poisoning; we shall
therefore consider the chemical history of these different preparations
separately, and then describe the symptoms which they generally
occasion.
_Liquor Potassæ._
This may be considered as a nearly pure solution of potass, although, as
it is usually prepared, it contains small portions of _muriate_ and
_sulphate of potass_, _silica_, and _lime_. It is a limpid, dense,
colourless solution; when rubbed between the fingers it feels soapy, in
consequence of a partial solution of the cuticle. As it constitutes a
medicine in common use, and, moreover, forms the basis of many _quack
medicines_, as well as of those preparations which are sold under the
name of _Depilatories_, it may readily become the accidental instrument
of mischief.
_Chemical Tests for its detection._
There cannot exist any difficulty in this investigation; its highly
alkaline characters will be immediately announced by its effects on the
vegetable test papers, and by its power of saturating acids; while the
particular species of alkali may be readily identified by the following
reagents.
(_a_) _Carbonic acid; or water saturated with the gas._ This will not
produce any[331] disturbance in the solution of potass; a fact which at
once serves to distinguish this alkali from the earths, _baryta_ and
_lime_.
(_b_) _Deuto-muriate of Platina_ occasions a canary-yellow precipitate,
consisting of the deutoxide of platina, potass, and muriatic acid; as
this precipitate is, to a certain extent, soluble in water, the test may
fail through dilution. With soda, this reagent will not occasion any
precipitate, a fact which depends upon the solubility of the triple salt
formed, and affords an easy method of distinguishing the fixed alkalies
from each other.
(_c_) _Tartaric acid._ If an excess of this acid be added, we shall
obtain crystals of a _bi-tartrate_; a phenomenon which will not take
place if soda be the alkali employed.
_Potassa Fusa_, or _Kali Causticum_.
This substance, which occurs in sticks, or cylinders, is an extremely
caustic and deliquescent substance; it is principally employed in
surgery, to establish an ulcer; or, instead of incision, to open a
tumour. See _Pharmacologia_. As it differs from potass, only in the
degree of purity, it is unnecessary to offer any farther remarks.
_Potassa cum Calce._
This is a mixture of the preceding substance with lime, which is added
with a view to diminish the deliquescent property of the alkali, and
thus to render it more manageable as an escharotic. There will be no
difficulty in separating these ingredients. Their different solubilities
will furnish an easy mode of effecting it to a certain extent, and we
may then precipitate the remaining portion of lime, by carbonic acid.
_Sub-carbonate of Potass_—_Salt of Tartar_—_Pearl-ash_—_Potash_.
Although potass becomes comparatively mild, by its union with carbonic
acid; yet the present preparation retains so much causticity as to
render it poisonous, if administered in any considerable dose. _Plenck_
reports a case of this kind, where a patient having swallowed an ounce
of _salt of tartar_, was shortly afterwards seized with a violent
vomiting, which continued for forty-eight hours, followed by a violent
inflammation of the stomach; from which, however, he ultimately
recovered.
_Symptoms of Poisoning by any of the above preparations of Potass._
A styptic, urinous, and caustic taste; a severe heat in the throat;
violent vomiting, generally of alkaline matter, turning the syrups of
violets green, and where the alkali has been in the state of
_carbonate_, effervescing with acids; sometimes the matter thus ejected
is mixed with blood; copious alvine evacuations; severe pain in the
epigastric region; excruciating tormina of the bowels; depravation of
the intellectual faculties, and death. It will be easily perceived that
the above symptoms merely indicate the operation of a corrosive poison.
They offer no characteristic peculiarities which can enable us to decide
upon the particular substance that has been swallowed, unless, indeed,
the matter vomited can be submitted to examination.
_Antidotes._
From the experiments of _Orfila_, it appears that vinegar, diluted with
water, is the remedy which can be administered with the greatest
success, where any preparation of this alkali has been swallowed in a
poisonous dose.
_Organic lesions discovered on dissection._
In consequence of the peculiar action of this alkali upon animal matter,
we shall generally find the stomach perforated, and its coats
extensively dissolved. We shall moreover discover the usual indications
of violent inflammation in this viscus, as well as in the intestines.