PRUSSIC ACID.—A poisonous acid occurring naturally in oil of bitter almonds, in the bark of wild cherry, in the leaves of the cherry-laurel, and in a number of seeds of the rose family. Artificially it is prepared from the cyanides. Prussic acid is not by any means the most poisonous substance known, most of the alkaloids being, weight for weight, much more powerful ; but it is an extremely active poison in small doses (r to 2 grains) and usually kills very rapidly. The symptoms of acute poisoning usually come on very promptly. The patient often collapses suddenly, with symptoms of extreme weakness and heart stoppage, the lips being usually red. In sub-acute poison ing, nausea and vomiting may presage the very marked weakness and giddiness ; and the patient may be dizzy for some time before losing con sciousness. The only practical treatment is by prompt evacuation of the stomach, the administration of stimulants (alcoholic drinks, coffee, etc.), the application of heat, and hot enemas of salt water.
PTOMAINE-POISONING.—Ptomaine is a poisonous alkaloid which is present in decomposing animal matter. The eating of decayed meat, fish, oysters, cheese, etc., may give rise to acute poisoning. Although the mani festations of disease are not alike in all such instances, some of them are almost invariably observed in all cases. The symptoms may begin as early as half an hour after the ingestion of the poisonous food, hut they usually appear some time during the first twenty-four hours. They consist in nausea, retching and vomiting, and usually violent diarrhoea resembling an attack of cholera. In some cases, however, there is persistent constipation.
Severe lassitude and general weakness ensue, followed by violent thirst, chills, dilatation of the pupils, dizziness (even when lying down), drooping of the upper eyelids, difficulty of breathing, twitching of the muscles, paralysis of the limbs, and convulsions. Many cases (such as those following poisoning from fish or oysters) are accompanied by fever, and are further characterised by skin eruptions which later peel off. These poisonings are always very dangerous, and may terminate fatally in from one to fourteen clays. Some cases, however, may be cured within a few hours. It is necessary in all cases to call a physician as quickly as possible, as nothing can be expected from the use of domestic remedies except from such measures as tend to induce or promote vomiting.
Unfortunately, little can be said with reference to the prevention of this form of poisoning. It is self-evident that soft and stinking meat, sausages which are jelly-like and smeary within, and decayed fish must not be eaten. But it is very often the case that the decayed condition of these food stuffs can be recognised neither by inspection nor by taste and smell. Nor is their preparation a protection, for many cases are on record in which poisoning has been caused by cooked as well as by smoked meat, fish, sausages, etc. The most dangerous articles of food are the brain, sweetbreads, and liver of animals ; the roe of fish ; and sausages.