820 
POISON. 
to them, tinctures them neverthelefs with a poifon deadly 
to many other creatures. Accordingly the alimentary tube 
is more poifonous than any other part of fiffi, the mufcular 
parts being only (lightly tin&ured. It is a curious circum- 
ftance,that the fame fifh,which is perf^&ly innocuous at one 
period, may and often is highly pernicious at another. Cer¬ 
tain and rapid death is almofl fure to enfue from eatingthe 
yellow-bill fprat; but, from a ufe of mod other kinds of 
poifonous fiffi, the perfon is feized after a few hours with 
languor, heavinefs, and faintnefs, fucceeded by great reft- 
leffnefs, flu things in the face, giddinefs in the head, car- 
dialgia, naufea, griping pains in the bowels, and a fevere 
vomiting and purging. The burning, which was felt at 
firlt only in the face and eyes, is at length extended over 
the whole body, but more particularly the palms of the 
hands and foies of the feet, and is often fucceeded by an 
eruption or efflorefcence, riling up in large bumps fimilar 
to bug-bites, or the nettle-rath. The pulfe is ufually 
hard and frequent at firft, but it foon becomes low and 
feeble. With the ardor of the (kin, there is invariably a 
prickly fenfation in the hands when immerfed in cold 
water, which particular fymptom may always enable us 
to decide with confidence on the real nature of the dif- 
eafe. In fome cafes, the neck of the bladder, urethra, 
and fphinfter ani, are likewife affefled with ardor, and 
the patient experiences a difficulty of making water, 
together with a confiderable degree of tenefmus. In the 
advanced (lagefofthedifeafe, the whole furface of the body 
acquires a deep yellow hue as in jaundice, and the urine 
is likewife highly tinged of the lame colour. Even perfo¬ 
ration gives a deep yellow tinge to the patient’s linen. 
Theie are the only animal poifons belonging to this clafs. 
They require the fame treatment, as to vomiting, with 
the vegetable poifons. Afterwards (Emulation, or, as the 
cafe requires, antiphlogiffic meafitres, are indicated. As 
the poifon generally paffes in large proportions to the 
bowels before fymptoms occur, purging is always requi- 
fite; and this ffiould be produced by the mod draftic 
cathartics. The fpirit of turpentine mixed with half 
its quantity of aether is an excellent ftimulus in thefe 
cafes, and alfo when the nux vomica has been taken. 
In the treatment of a cafe of poifoning, the detcclion of 
the poifon itfelf is of great importance. If any confider- 
able portion of the poifon is found, the ufuai difcrimi- 
nating marks, of colour, weight, tafte, and external cha- 
rafrer, (with which it is prefumed that every practitioner 
is acquainted, though they cannot be reduced to writing,) 
are fufficient guides of practice. But, when only a fmall 
quantity remains, when death has followed, and powerful 
vomiting has completely emptied the ftomach, we re¬ 
quire tells of the utmoll delicacy, and, of courfe, as the 
lives of our fellow-creatures are fo often implicated, of 
the greeted poffible infallibility. 
Many writers recommend, that, as the detection of 
poifons requires a degree of taft only to be attained by 
condant practice in the operations of chemidry, and as 
moreover it requires a general and profound knowledge 
of that fcience, only to be gained by an undivided ftudy 
of it, it would be better were medical practitioners en¬ 
tirely to abdain from the attempt. It is advifed, that, 
having contented themfelves with affiduoudy procuring 
every lubdance in which the poifon adminidered may be 
contained, they (liould let the ted of detecting its nature 
devolve on the profeffional chemill. This is certainly very 
proper, independent of the faffs jud dated, with regard 
to the general inexperience of the medical profeffion. 
There is alfo greater fecurity for judice, when this im¬ 
portant analyfis is intruded to one who has imbibed no 
prejudices from foreign circumltances, and who there¬ 
fore forms an impartial judgment from inclusions 
reding on his own fcience. Neverthelefs it is to be wiflied, 
that the modes of chemical analyfis (hould be as much as 
poffible known to the medical profeffion, as there are 
times and (ituations in which a man mud act for himfeif. 
We therefore fubjoin a fuccinCt account of the analyfis 
of poifons; but, as this is written for the profeffion, we 
of courfe add the appearances which diffeftion exhibits. 
It is proper to remark, however, that both thefe ufeful 
guides mud in many indances be difpenfed with ; for che¬ 
mical analyfis can only (at prefent) be fatisfaCtorily ap¬ 
plied to mineral poifons ; and the appearance which 
mod poifons exhibit after death may refult from difeafe. 
But it ffiould be remembered, that fudden indammation 
of the domach, terminating foon in death, exhibiting on 
diffeCtion, erofion, ulceration, or mortification, of that 
organ, are fcarcely ever feen in this country, and ffiould 
therefore excite the higheft degree of fufpicion that 
poifon is the caufe. The fubdances which are fubjeCt 
to analyfis are the food or drink of which the patient has 
partaken, the contents of the domach, or, if empty, the 
domach itfelf. In both thefe cafes it is neceffary to 
diffolve and feparate the poifon before it is fubjeCted to the 
ted. We (hall (how the method of doing this prefently, 
when fpeaking of arfenic. 
Acids change the blue colour of the tinCture of lit¬ 
mus, turnfole, or the infufion of red cabbage, to red. 
Sulphuric acid has no odour; heated with charcoal, it 
difengages the fame fmell as fulphur when burnt. Ni¬ 
trous acid, poured upon copper, effervefces, and gives 
rife to copious vapours of an orange colour. The more 
perfect acid (nitric acid) is colourlefs; but, poured upon 
copper, it has the fame effect. Concentrated muriatic acid 
gives off whitilh vapours, and, mixed with a folution of 
nitrate of (liver, throws down a white, heavy, and 
curdled, precipitate, which cannot be diffolved in water 
or nitric acid. Aqua regia, or nitro-mutiatic acid, adds 
upon copper in the fame manner as nitric acid. Fluoric 
acid corrodes glafs. Oxalic acid heated in a tube, is al- 
mod entirely volatilized, a fmall portion is decompofed, 
and a little charcoal is left behind; a folution of the 
acid in diddled water, added to lime-water, caufes a 
white precipitate, which is not re-dijjolved by an accefs of 
oxalic acid. 1'artaric acid is entirely decompofed by 
heat, and leaves much carbon ; added to lime-water, it 
occafions a precipitate, which is eafily re-dil]'olved by an 
excefs of acid. Citric acid is decompofed by heat, and 
docs nut precipitate lime-water, unlefs added in folid 
lumps, or when the-mixture is heated. 
The Alkalies, diffolved in pure water, turn fyrupof 
violets green. The volatile alkali is readily difeovered by 
its ftrong odour. A yellow precipitate appears when 
nitro-muriate of platina is dropped into a folution of 
fulphate of potaJh\ while no fuch precipitate is formed 
with the folution of fulphate of J'odd. Neither the one 
nor the other is changed by fulphuric or carbonic acids. 
From lime-water a white precipitate is thrown down by 
adding carbonic acid or any of the carbonates,' and it is 
not vilibly afteCted by the addition of fulphuric acid. 
Turmeric is a very delicate tell for alkalies, and, oh the 
whole, perhaps the be(f. The natural colour of a fpi- 
rituous or watery infufion is yellow, which is changed 
to a brick or orange red by alkalies. 
Mercurial Preparations .—All the mercurial preparations 
heated to rednefs in. a glafs tube with potaffi are decom¬ 
pofed ; and the metal, which is feen (licking to the edge, 
becomes quickly volatilized. Corrofive fublimate is white, 
and may be diffolved in water; potaffi added to this lo- 
lution caufes a, light yellow precipitate, and ammonia 
a white precipitate. A very fmall quantity of a dilute 
folution of fubcarbonate of potaffi, (fait of tartar,) fuch 
as a (ingle drop, added to a folution of corrofive fublimate, 
will produce a white precipitate; but, on a (till further 
addition of alkali, an orange-coloured fediment will be 
formed. On the addition of lime-water to the folution 
of corrofive fublimate, a precipitate of an orange-yellow 
colour will inffantly appear. It ffiould alfo be remarked 
in contradiftinCtion to arfenic, that fulphuretted water 
throws down from a folution of corrofive fublimate a 
dark-coloured fediment, which, when dried and (trongly 
heated, is wholly volatilized, without any odour of arfenic. 
z Red 
