Aids To Forensic Medicine And Toxicology Part 22

_Symptoms._--Sense of suffocation, twitchings of muscles, followed by tetanic convulsions and opisthotonos, each lasting half to two minutes.

Mental faculties unaffected, face congested and anxious; eyes staring, lips livid; much thirst. The period of accession of the symptoms varies with the mode of administration of the poison. Symptoms, as a rule, come on soon after food has been taken. Patient may die within a few hours from asphyxia or from exhaustion.

In _Teta.n.u.s_ there is usually history of a wound; the symptoms come on slowly; lockjaw is an early symptom, and only later complete convulsions; the intervals between the fits are never entirely free from rigidity. Death is delayed for some days.

_Post-Mortem Appearances._--Heart empty, blood fluid, rigor mortis persistent. Hands usually clenched; feet arched and inverted. Congestion of brain, spinal cord, and lungs.

_Treatment._--Emetics or stomach-pump if the patient is deeply anaesthetized. Tannic acid and permanganate of pota.s.sium. Bromide of pota.s.sium 1/2 ounce with chloral 30 grains, repeated if necessary.

_Fatal Dose (Smallest)._--Quarter of a grain.

_Fatal Period (Shortest)._--Ten minutes; usually two to four hours.

_Method of Extraction from the Stomach._--The alkaloid may be separated by the process of Stas-Otto.

_Tests._--Strychnine has a characteristic, very bitter taste; it imparts this taste to even very dilute solutions; it is unaffected by sulphuric acid, but gives a purple-blue colour, changing to crimson and light red, when the edge of this solution is touched with dioxide of manganese, pota.s.sium b.i.+.c.hromate, ferricyanide of pota.s.sium, or permanganate of pota.s.sium. This test is so delicate as to show the 1/25000 of a grain of the alkaloid. A very minute quant.i.ty (1/5000 grain) in solution placed on the skin of a frog after drying causes tetanic convulsions.

=Brucine.=--This alkaloid, found a.s.sociated with strychnine, possesses the same properties, though in a less powerful degree. Nitric acid gives a blood-red colour, changed to purple with protochloride of tin.

XLV.--CANTHARIDES

=Cantharides.=--Spanish fly, or blistering beetle, is the basis of most of the blistering preparations. It is sometimes taken as an abortifacient or given as an aphrodisiac, but whether it has any such action is open to question. It acts as an irritant to the kidneys and bladder, and sometimes produces haaematuria and a good deal of temporary discomfort.

_Symptoms._--Burning sensation in the throat and stomach, with salivation, pain and difficulty in swallowing. Vomiting of mucus mixed with blood. Tenesmus, diarrhoea, the motions containing blood and mucus.

Dysuria, with pa.s.sage of small amounts of alb.u.minous and b.l.o.o.d.y urine.

Peritonitis, high temperature, quick pulse, headache, loss of sensibility, and convulsions.

_Post-Mortem._--Gastro-intestinal mucous membrane inflamed, with gangrenous patches. Genito-urinary tract inflamed. Acute nephritis.

_Treatment._--An emetic of apomorphine; demulcent drinks, such as barley-water, white of egg and water, linseed-tea and gruel (but not oils), with a hypodermic injection of morphine to allay pain.

_Tests._--The vomited matter often contains s.h.i.+ning particles of the powder. The urine will probably be alb.u.minous.

XLVI.--ABORTIFACIENTS

Emmenagogues are remedies which have the property of exciting the catamenial flow; ecbolics, or abortives, are drugs which excite contraction of the uterus, and are supposed to have the power of expelling its contents. The vegetable substances commonly reputed to be abortives are ergot, savin, aloes (Hierapicra), digitalis, colocynth, pennyroyal, and nutmeg; but _there is no evidence to show that any drug possesses this property_. Lead in some parts of the country is a popular abortifacient. A medicine may be an emmenagogue without being an ecbolic. Permanganate of pota.s.sium and binoxide of manganese are valuable remedies for amenorrhoea, but will not produce abortion. The vegetable substances frequently used as abortives are savin and ergot.

=Savin= (_Juniperus Sabina_).--Leaves and tops of the plant yield an acrid oil having poisonous properties, and which has even produced death.

_Symptoms._--Those of irritant poisons. Purging not always present, but tenesmus and strangury.

_Post-Mortem Appearances._--Acute inflammation of alimentary ca.n.a.l.

Green powder found. This, washed and dried and then rubbed, gives odour of savin.

_Test._--A watery solution of savin strikes deep green with perchloride of iron, and if an infusion of the twigs has been taken the twigs may be detected with the microscope. The twigs obtained from the stomach, dried and rubbed between the finger and thumb, will give the odour of savin.

=Ergot= (_Secale Cornutum_).--A parasitic fungus attacking wheat, barley, oats, and rye, which is reputed to have the power of causing contraction of unstriped muscular fibre, especially that of the uterus.

_Symptoms._--La.s.situde, headache, nausea, diarrhoea, anuria, convulsions, coma. Small quant.i.ties frequently repeated have in the past produced gangrene of the extremities, or anaesthesia of fingers and toes.

_Tests._--Lake-red colour with liquor pota.s.sae; this liquid filtered gives a precipitate of same colour with nitric acid.

XLVII.--POISONOUS FUNGI AND TOXIC FOODS

=Fungi.=--Of the poisonous mushrooms, the _Amanita phalloides_ and the fly agaric, or _Agaricus muscarius_, are the most potent. The active principle of the former is _phallin_, and of the latter _muscarine_. The _Amanita phalloides_ is distinguished from the common mushroom (_Agaricus campestris_) by having permanent white gills and a hollow stem. The _Agaricus muscarius_ is bright red with yellow spots. Phallin is a toxalb.u.min which destroys the red blood-corpuscles, causing the serum to become red in colour and the urine blood-stained. Fibrin is liberated, and thromboses occur, especially in the liver. The symptoms may be mistaken for phosphorus-poisoning or acute yellow atrophy of the liver. Muscarine affects the nervous system chiefly.

_Edible fungi_ have an agreeable taste and smell, and are firm in substance. _Poisonous fungi_ have an offensive smell and bitter taste, are often of a bright colour, and soon become pulpy.

_Symptoms._--These may be of the narcotic or irritant types. Usually, however, there is violent colic, with thirst, vomiting, and diarrhoea, mental excitement, followed by delirium, convulsions, coma, slow pulse, stertorous breathing, cyanosis, cold extremities, and dilated pupils.

_Post-Mortem._--In phallin-poisoning the blood remains fluid; numerous haemorrhages are present, with fatty degeneration of the internal organs.

_Treatment._--Use the stomach-tube to give a solution of permanganate of potash, emetics, followed by a hypodermic injection of 1/50 grain of atropine. Transfusion of saline fluid. A dose of castor-oil would be useful.

=Foods.=--The kinds of food which most frequently produce symptoms of poisoning are pork, veal, beef, meat-pies, potted and tinned meats, sausages, and brawn. Sausage-poisoning is common in Germany. It is not necessary that the food should be 'high' to give rise to poisoning. It may arise from the use of the flesh of an animal suffering from some disease, from inoculation with micro-organisms, or from the presence of toxalb.u.moses or ptomaines. Many diseases, such as diarrhoea, enteric fever, and cholera, and perhaps tuberculosis, may be caused by eating infected food. Trichiniasis may also be mentioned. Tinned fish often gives rise to symptoms of poisoning, and sh.e.l.l-fish are not uncommonly contaminated with pathogenic micro-organisms. Mussel-poisoning was formerly supposed to be due to the copper in them derived from s.h.i.+ps'

bottoms, but it is more probably the result of the formation of a toxine during life, and not after decomposition has set in. Milk, too, may give rise to gastro-intestinal irritation from the occurrence in it of chemical changes. There have been epidemics of poisoning from eating cheese containing _tyrotoxicon_. Ergotism from eating bread made with ergotized wheat is now rare, but _pellagra_ from the consumption of mouldy maize, and _lathyrism_, due to the admixture with flour of the seeds of certain kinds of vetch, are still common in Southern Europe.

_Symptoms._--The symptoms which result from the ingestion of poisonous meat are often very severe. In some cases their appearance is delayed from twenty-four to forty-eight hours. They may resemble those of an infectious disease or those of acute enteritis. Usually there are headache, anorexia, rigors, intestinal disturbance, pains in the back and limbs, and delirium. Sometimes the symptoms resemble atropine-poisoning, a condition due to ptomatropine.

_Treatment._--Emetics, purgatives, stimulants, with hypodermic injections of strychnine and atropine along with stimulants.

XLVIII.--PTOMAINES OR CADAVERIC ALKALOIDS

Every medical man, before presenting himself to give evidence in a case of suspected poisoning, should make himself thoroughly acquainted with recent researches on the subject. Ptomaines are, for the most part, alkaloids generated during the process of putrefaction, and they closely resemble many of the vegetable alkaloids--veratrine, morphine, and codeine, for example--not only in chemical characters, but in physiological properties. They are probably allied to neurine, an alkaloid obtained from the brain and also from the bile. Some of them are a.n.a.logous in action to muscarine, the active principle of the fly fungus. Some are proteids, alb.u.mins, and globulins. Ptomaines may be produced abundantly in animal substances which, after exposure under insanitary conditions, have been excluded from the air. Ptomaines or toxalb.u.mins are sometimes found in potted meats and sausages, and are due to organisms--the _Bacillus botulinus_, the _B. enteritidis_ of Gartner, the _B. proteus vulgaris_, or the _B. aertrycke_ (which is perhaps the most common of all). The symptoms produced by the latter are usually vomiting, abdominal pain, pains in the limbs and cramps, diarrhoea, vertigo, coldness, faintness, and collapse. The symptoms of _botulism_ are dryness of skin and mucous membranes, dilatation of pupils, paralysis of muscles, diplopia, etc. Articles of food most often a.s.sociated with poisoning are pork, ham, bacon, veal, baked meat-pie, milk, cheese, mussels, tinned meats.

In a case of suspected poisoning, counsel for the defence, if he knows his work, will probably cross-examine the medical expert on this subject, and endeavour to elicit an admission that the reactions which have been attributed to a poison may possibly be accounted for on the theory of the formation of a ptomaine. There is practically no counter-move to this form of attack.