Shell Fish have been greatly extolled by some physicians, as nutritive and easily-digestible articles of food. It will be necessary to examine this question, by the application of those principles which I have endeavoured to establish. Oysters, in my opinion, enjoy a reputation which they do not deserve: when eaten cold, they are frequently distressing to weak stomachs, and require the aid of pepper as a stimulant; and since they are usually swallowed without mastication, the stomach has an additional labour to perform, in order to reduce them into chyme. When cooked, they are still less digestible, on account of the change produced upon their albuminous principle. It is, however, certain, that they are nourishing, and contain a considerable quantity of nutritive matter in a small compass; but this latter circumstance affords another objection to their use. Certain it is, that oysters have occasionally produced injurious effects, which have been attributed to their having lain on coppery beds: but this idea is entirely unfounded, and arose merely from the green colour which they often acquire, the cause of which is now generally understood; it is sometimes an operation of nature, but it is more generally produced by art, by placing them in a situation where there is a great deposite from the sea, consisting of the vegetable germs of marine conferva and fuci,, and which impart their colour to the oyster.

For this object, the Dutch formerly carried oysters from our coasts, and deposited them on their own. Native oysters, transported into the Colchester beds, soon assume a green colour. Where this food has produced a fit of indigestion, it has evidently arisen from the indigestible nature of the oyster, and the state of the individual's stomach at the time; and had such a person indulged to the same amount, in any equally indigestible aliment, there can be no doubt but that he would have experienced similar effects. Dr. Clarke has related 1 some striking cases of convulsion, which occurred to women after child-birth, in consequence of eating oysters: the same effects might have supervened the ingestion of any food that is not easily digestible; for the stomach of a woman at such a period, in consequence of the irritable state of the nervous system, is easily disturbed in its functions. The oyster casts its spawn, which the dredgers call the spat, in the month of May, after which they are sick and unfit for food; but in June and July they begin to mend, and in August they are perfectly well. We therefore see the cause of their going out of season, and discover the origin of the old maxim, that an oyster is never good except when there is an R in the month.

Lobsters are certainly nutritive; but they are exposed to the same objection, on the ground of indigestibility; and such has been their effect upon certain stomachs, as to have excited a suspicion of their containing some poisonous principle: they have been known to occasion pain in the throat, and, besides eruptions upon the skin, to extend their morbid influence to the production of pain in the stomach, and affection of the joints. As found in the London market, they are generally underboiled, with a view to their better keeping; and in that case they are highly indigestible. The same observations apply to the crab. Shrimps are a species of sea crab, which vary in their colour and size, and are considered easier of digestion than the preceding articles. The muscle is a species of bivalve which is more solid, and equally as indigestible as any animal of the same tribe. The common people consider them as poisonous, and, in eating them, take out a part in which they suppose the poison principally to reside. This is a dark part, which is the heart, and is quite innocuous: the fact, however, is sufficient to prove, that this species of bivalve has been known to kill; but probably not more frequently than any other indigestible substance.

Our annals abound with instances of the deleterious properties of melons, cucumbers, etc, and yet no one will contend that any poison, properly so called, resides in such vegetables. The peculiar cutaneous efflorescence which is produced by the imperfect digestion of shell-fish, has been observed to occur more frequently in cases where the fish has been stale or tainted1; although it also happens where no such error can be suspected.

1 Medical Transactions of the College of Physicians, vol. v.

1 I am inclined to think that, under such circumstances, an absolute poison may be occasionally generated. Without this concession, it will be impossible to explain many of the phenomena of fish-poison. Dr. Burrows has published a very striking case, in which two youths of the ages of nine and fourteen died, in consequence of eating about a dozen of small muscles, which they had picked from the side of a fishing-smack at Gravesend. The muscles were found to have been in a putrid state. In the Gazette de Sante', and in the works of Fodere and Behren, similar cases are recorded. Vancouver, in his voyage to the coast of America, relates, that several of his men were ill from eating some muscles which they had collected and roasted for breakfast; in an hour after which, they complained of numbness of the face and extremities, sickness and giddiness. Three were more affected than the others, and one of them died. A question has long since arisen, how far the ingestion of animal matter in a state of putrefaction is liable to affect the health. I am strongly inclined to believe that the muscular fibre does not become poisonous under such circumstances, but I would not extend this remark to the brain and viscera.

In Crantz's History of Greenland, we read an account of the death of thirty-two persons, at a missionary station, called Kangek, shortly after a repast upon the putrid brains of a walrus. Some highly interesting observations have lately been published by Dr. Kerner of Wurtemberg, respecting the probable existence of a species of animal poison hitherto unknown. He informs us that the smoked sausages, which constitute so favourite a repast in his country, often cause fatal poisoning. The effects of the poison occasionally manifest themselves in the spring, generally in the month of April, in a degree more or less alarming. He states that out of seventy-six persons, who became sick from eating such sausages, thirty-seven died in a short time, and that several others remained ill for years. Upon these occasions it has been observed that the most virulent sausages were made of liver. M. Cadet, of Paris, analyzed all the meat, examined all the vessels in which they had been prepared, and inspected the matters vomited, or found in the stomach after death, without being able to trace the vestige of any known poison; nor was there the slightest evidence, in these cases, of malevolence or negligence.