The mode in which the formation of these acids is accounted for is as follows. According to the researches of Proust the sharp peculiar taste of old cheese is owing to the gradual conversion of the curd or casein into the caseate of ammonia, which in sound cheeses is always united with the excess of alkali. In the cheese in question (barscher-käse, quark-käse, hand-käse) the curd, before being salted, is left for some time in a heap to ferment, in consequence of which it becomes sour and afterwards ripens faster. But if the milk has been curdled with vinegar,—if the acid liquor formed while it ferments is not carefully drained off,—if the fermentation is allowed to go too far,—if too little salt is used in preserving the curd,—or if flour has been mixed with the curd, the subsequent ripening or decaying of the cheese follows a peculiar course, and a considerable excess of caseïc acid is formed, as well as some sebacic acid.
The poisonous cheeses, according to Westrumb, present no peculiarity in their appearance, taste or smell. But Hünefeld says that they are yellowish-red, soft, and tough, with harder and darker lumps interspersed, that they have a disagreeable taste, redden litmus, and becomes flesh-red instead of yellow, under the action of nitric acid.
The symptoms they cause in man appear to be nearly the same with those produced by the poisonous sausage, and usually commence, according to Hünefeld, in five or six hours, according to Westrumb in half an hour. They constitute various degrees and combinations of gastro-enteric inflammation. In the most severe of Hünefeld’s cases the quantity taken did not exceed four ounces, and was sometimes only an ounce.
The same author found that a drachm and a half of the caseïc acid, which he procured from the cheese, killed a cat in eight minutes, and the same quantity of the sebacic acid another in three hours. His experiments, however, are not quite conclusive of the fact that these acids are really the poisonous principles, as he has not extended his experimental researches to the caseïc and sebacic acids prepared in the ordinary way. His views will probably be altered and simplified, if future experiments should confirm the late inquiries of Braconnot, who has stated that Proust’s caseïc acid is a modification of the acetic, combined with an acrid oil.[[1578]] Westrumb procured analogous results with those of Hünefeld when he gave to animals the acid fat which he separated in the course of his analysis.
The poisonous cheese has been hitherto met with chiefly in some parts of Germany. From information communicated to me by Dr. Swanwick of Macclesfield, there is some reason to think that a parallel poison is occasionally met with in Cheshire, among the small hill-farms, where the limited extent of the dairies obliges the farmer to keep the curd for several days before a sufficient quantity is accumulated for the larger cheeses.—I am indebted to Mr. Wilson of Lockerby for the particulars of a set of cases, which seem to have been owing to some obscure poison in cheese. A gentleman, an hour after eating the suspected cheese, was seized with extreme weakness and severe vomiting for four hours, then with general soreness and a mercurial taste in the mouth, and afterwards with tenesmus, bloody stools, soreness of the gums, and cramps in the limbs; from which symptoms he did not recover for four weeks. Five other members of his household suffered similarly, but less severely, and also the shop-boy who ate a little while selling it. None of the ordinary mineral poisons could be detected in it.—It is hardly necessary to add, that analogous properties may be imparted to cheese by the intentional or accidental addition of other poisons of a mineral nature. This subject has been already alluded to in the section upon lead.
As connected, though indeed but remotely, with the cheese-poison, some notice may be here taken of a peculiar mode in which it has been supposed that milk may acquire the properties of an acrid poison. It has been several times remarked on the continent, that the milk even of the cow, but more particularly that of the ewe and goat, may act like a violent poison, although no mineral or other deleterious impregnation could be detected in it; and these effects have been variously and vaguely ascribed to the animal having been diseased, or to its having fed on acrid vegetables, which pass into the milk without injury to its health, because though poisonous to most animals, they are not so to the Ruminantia. This singular topic cannot be thoroughly investigated, as precise facts are still wanting. But the two following examples of the accident alluded to may be mentioned. One occurred at Aurillac, a village in France. Fifteen or sixteen customers of a particular dealer in goats’ milk were at one and the same time attacked with all the symptoms of violent cholera; and about twenty-four hours afterwards the goat too was taken ill with the same affection, and died in three days.[[1579]] The other instance occurred at Hereford in Westphalia. Six people of a family, after partaking of goat’s butter-milk, were simultaneously attacked with violent vomiting, tension of the epigastrium, and retraction of the lower belly; and several of them suffered so severely as even to have been thought by their physician, Dr. Bonorden, to be in danger.[[1580]] Dr. Westrumb has alluded to similar cases in his memoir on the poison of cheese, and has proved that the ordinary explanations of them are far from satisfactory. Among other judicious observations he remarks, that the poison has been generally believed to arise sometimes from the cattle having fed on the Euphorbia esula, a species of spurge; that, according to Viridet in his Tractatus de Prima Coctione, l. i. c. 15, certain fields in the neighbourhood of Embrim were of necessity abandoned by the shepherds, because the milk of their cows was rendered useless by the abundance of that plant among the herbage; but that he himself has found cattle will not touch it so long as grass and other wholesome vegetables are to be found in the pasturage.[[1581]] Professors Orfila and Marc, who were appointed by the Society of Medicine of Paris to report upon the accident at Aurillac, state, that in parallel cases which had been referred to them by the police at Paris they had been unable to detect any mineral poison; that none of the received explanations are in their opinion satisfactory; and that they are disposed to ascribe the poisonous alteration of the milk to new principles formed by a vital process.
Another common article of food, which has occasionally produced similar effects with the poisonous sausages and cheese, is bacon. Dr. Geiseler has related an accident which occurred in a family of eight persons, and which he traced to this cause. The symptoms were almost exactly the same with those described by Kerner, with the addition, however, of delirium and loss of recollection; and in two they were so violent as seriously to endanger life. The father of the family alone escaped, having stewed his bacon, while the rest ate it raw.[[1582]] His escape might have arisen from the fatty acid having been decomposed, or the acrid oil expelled, by the heat. It is not improbable that other varieties of cured meat may also become poisonous. Cadet de Gassicourt mentions, that he had been frequently desired by the police to examine cured meat which had produced symptoms of poisoning at Paris,[[1583]] and Orfila makes the same remark in his Lectures on Medical Jurisprudence.[[1584]] As the meat always came from the shops of meat-curers, and did not contain any mineral poison, it probably owed its qualities to the same ingredient as the bacon in Geiseler’s cases. A full and interesting account of an accident of the kind has also been given by M. Ollivier, of which the following is an analysis. Three members of a family at Paris, on the day after eating a ham-pie, were seized with shivering, cold sweats, violent pain in the stomach, frequent vomiting, burning thirst, excessive tenderness of the belly, profuse purging, and colic; but they all recovered under antiphlogistic treatment. On subsequent inquiry it appeared that about the same period other customers of the pastry-cook who supplied the pie had been similarly affected; and consequently an investigation was made into the cause under the authority of the police. After a very careful analysis, however, by MM. Barruel and Ollivier, it was clearly made out, that the pie did not contain a trace of any of the common mineral poisons; and therefore the only conclusion Ollivier conceived it possible to draw was, that the ham had acquired the properties of the poisonous sausage or cheese of Germany.[[1585]] Two similar reports have been since published, one by MM. Lecanu, Labarraque, and Delamorlière, another by Chevallier; and both agree in ascribing the poisonous effects to the decay of the meat, the ordinary poisons having been sought for in vain. In the cases examined by Chevallier, the article was a sort of sausage, called in Paris “Italian Cheese,” and made of scraps of various kinds of meat, especially pork.[[1586]] M. Boutigny has published an account of a similar accident which befel a great number of people at a festival in France. He could not find any of the ordinary poisons in the meat, which had been taken chiefly in the form of sausages; and being consequently persuaded that the suspected articles were wholesome, he dined on stuffed turkey, sold by the dealer who had supplied them. But he was seized with chilliness, contracted pulse, cold sweating, lividity of the countenance, great anxiety, and then with vomiting and purging; after which he slowly recovered.[[1587]]
Other articles of food have been occasionally observed to act injuriously on the health. Thus M. Ollivier has given an account of a whole family having been apparently poisoned with mutton under the influence of modified decay. Six individuals were attacked soon after dinner with vomiting, purging, colic, tenderness of the belly, extreme prostration, and a small hurried pulse. Four of them died within eight days. General inflammatory redness, with some extravasation under the mucous coat, was found throughout the whole course of the small intestines. No trace could be detected of any of the ordinary poisons; and Ollivier was therefore led to ascribe the accident to some peculiar change produced in stewed mutton, which all the individuals had partaken of at dinner.[[1588]] In 1839 a singular accident happened at Zurich, which was ascribed to decayed veal and ham. On a fete-day 600 people, who had dined upon cold roast-veal and ham in a wooden erection, were all taken ill with shivering, giddiness, headache, burning fever, diarrhœa and vomiting; some had delirium, others a fœtid salivation and even ill-conditioned ulcers of the mouth; and in the worst cases collapse of the countenance, involuntary stools, and extreme prostration preceded death. On dissection the alimentary mucous membrane was found softened and the intestinal follicles ulcerated. The cause was supposed to have been satisfactorily traced to incipient putrefaction of the veal and ham, which constituted the fundamental part of the repast.[[1589]] Effects somewhat similar have been observed from spoiled goose-grease, used in dressing food. Dr. Siedler has related four cases where violent symptoms were thus induced. Two adults and two children, after eating a dish seasoned with goose-grease, were seized with giddiness, prostration of strength, anxiety, sweating,—burning pain in the lower belly, aggravated by pressure,—violent vomiting, in one case sanguinolent,—involuntary stools, and urine, and dilatation of the pupil. In one of the adults there was also complete insensibility, with imperceptible pulse for six minutes. No metallic poison could be found. The grease was acid, and of a repulsive odour; and three ounces given to a dog acted violently and in the same manner.[[1590]] Another article of food which has appeared occasionally to produce parallel effects is smoked sprats. An instance of their injurious operation is briefly described in the work quoted below;[[1591]] and Dr. O’Shaughnessey informed me some years ago, that, while in London, he met with the case of a female, advanced in pregnancy, who after eating smoked sprats, in which she remarked a disagreeable sharp taste, was attacked with severe colic, sickness, vomiting of food mixed with streaks and clots of blood, and some diarrhœa. Putrid pickled salmon has occasioned death in this country;[[1592]] and I may mention that I have known most violent diarrhœa occasioned in two instances by a very small portion of the oily matter about the fins of kipper or smoked salmon, so that I have no doubt a moderate quantity would produce serious effects.
Although these illustrations of the effects of modified putrefaction in rendering wholesome meat noxious have been taken in a great measure from continental experience, this has been done rather because the subject has been more fully and accurately investigated there, than because similar poisons are unknown in Britain. The defective system of medical police in this country would allow such accidents as those mentioned above to pass sometimes without notice, and almost always without scientific examination; but it must not therefore be supposed that they are wholly unknown.
The following incident, which happened a few years ago on the Galloway coast, is an instance of poisoning not less alarming than any of those which have occurred in Germany. In the autumn of 1826 four adults and ten children ate at dinner a stew made with meat taken from a dead calf, which was found by one of them on the sea shore, and of which no history could be procured. For three hours no ill effect followed. But they were then all seized with pain in the stomach, efforts to vomit, purging, and lividity of the face, succeeded by a soporose state like the stupor caused by opium, except that when roused the patient had a peculiar wild expression. One person died comatose in the course of six hours. The rest, being freely purged and made to vomit, eventually got well; but for some days they required the most powerful stimulants to counteract the exhaustion and collapse which followed the sopor. The meat, they said, looked well enough at the time it was used. Yet the remains of the fish which formed the noxious meal had a black colour and nauseous smell; and the uncooked flesh had a white, glistening appearance, and was so far decayed that its odour excited vomiting and fainting.[[1593]] It is much to be regretted that this accident was not properly inquired into. The only conjecture which the facts will warrant as to the cause of the poisonous quality of the meat is, that in consequence of having lain long in the water, the flesh had begun to undergo the adipocirous putrefaction; and that in the course of the changes thus induced the meat became impregnated with some poisonous principle, like that of the German sausages, or cheese.