is apt to cause indigestion in many persons who are not accustomed to it. But Dr. M'Divitt has shown by a number of interesting cases, that even in those habituated to its use, it may, from unascertained causes, excite symptoms closely allied to those of irritant poisoning. The effects sometimes begin within three hours, the symptoms being those of an affection of the stomach, such as sudden violent pain in the epigastrium, difficult breathing, irregularity of the pulse, great prostration and alarm, coldness of the extremities and vomiting. If a longer period elapses,—and sometimes no injury accrues for many hours, or even a whole day,—the symptoms indicate an affection of the abdomen, namely, pain in the region of the duodenum, or of the sigmoid flexure of the colon, with the other symptoms just enumerated, but which ere long become attended with more pungent pain, tension and tenderness of the belly, frequency of the pulse, and ineffectual straining to evacuate the bowels. In the less urgent and slower cases of this nature there is little or no vomiting. Sometimes nettle-rash appears. Stimulants, opiates, and bloodletting are of no avail; and the only useful remedies are emetics and cathartics, which speedily put an end to the symptoms by removing their cause. In all the cases related by the author the pork was either fresh or recently salted, fatter than usual, but not ill preserved or otherwise faulty in any appreciable respect. In every instance the individuals had eaten pork often before without injury; and on several occasions others ate without harm the same pork which seemed deleterious.
CHAPTER XXV.
OF POISONING BY MECHANICAL IRRITANTS.
The fifth order of the irritant class of poisons includes mechanical
irritants.
These substances have not properly speaking any poisonous quality; but occasion symptoms like those of poisoning, and even sometimes death itself, in consequence of their mechanical qualities only. They have therefore been excluded from every toxicological system proposed in recent times; but in a medico-legal work on poisoning it would be wrong to pass them without notice.
The most important of the mechanical irritants are those which cause injury by reason of their roughness, sharpness, or size.
Many instances have occurred of persons having swallowed fragments of steel, copper, iron, broken glass, or entire prune-stones, cherry-stones, and the like,—who not long afterwards were attacked with signs of inflammation, or some other abdominal disease, and were carried off by it as by the administration of poison. The disorders thus induced are almost always of a chronic or lingering kind, and commonly depend on gradual perforation of the intestines by the foreign body pressing on the coats. In general the illness ends in in-
