tagiousness of which is undoubted, notwithstanding the absence of this proof; as, for instance, the scarlet-fever and hooping-cough. But there are occasions when it is necessary to act on the supposition that a disease is contagious, though the evidence for this opinion is far short of proof. The question is sometimes so difficult-life and health are so precious-and the precautions necessary to prevent the communication of the disease, if it should be contagious, comparatively such trifling evils; that a prudent physician will take care to be on the safe side, and use measures as if he was certain it was contagious, although to an indifferent person, weighing the evidence in the scales of mere speculation, it would appear only a bare possibility;-and here is the difference between a science, which makes its experiments on retorts and receivers, things of clay and glass, and a science, the subjects of which are flesh and blood, and health and life; that whereas in the former, the onus probandi lies on him who affirms the proposition, because the disbelief of it leads to no injurious consequence; in the latter, the onus probandi sometimes lies with him who denies it, because the disbelief would occasion the neglect of measures, which are harmless even if they be unnecessary, but the neglect of which may be fatal if they be essential.

Five-and-twenty years ago Dr. Wells published his belief that erysipelas was sometimes contagious. The following is one of several facts which led him to this opinion:-An elderly man died of erysipelas of the face. His nephew, who visited him during his illness, was soon afterwards attacked by, and died of, the same disease. The wife of the old man was seized with the same disease a few days after his death, and died in about a week. The landlady of the same house was next affected with it and then her nurse, who was sent to the workhouse, where she died. Dr. Wells mentioned his suspicion to several medical friends, among whom were Dr. Pitcairn and Dr. Baillie, and they related to him several circumstances which had led them to a similar opinion.

Lying-in women are subject to a disease called puerperal fever. In general it is of unfrequent occurrence, and out of large numbers scarcely one suffers from it. There are times, however, when this disease rages like an epidemic, and is very fatal. At these times circumstances sometimes occur which create a strong suspicion that the disorder may be communicated by a medical attendant or nurse from one lying-in woman to another. We give the following, out of many authentic instances. A surgeon practising midwifery in a populous town, opened the body of a woman who died of puerperal fever, and thereby contracted an offensive smell in his clothes: nevertheless, surgeon-like, he continued to wear them

them, and to visit and deliver his patients in them. The first woman whom he attended after the dissection, was seized with, and died of, the same disease-the same happened to the second and the third. At length he was struck with the suspicion that puerperal fever might be contagious, and that he was carrying it from patient to patient in his offensive clothes;-he burnt them, and not another of his patients was affected.

These are incidents calculated to produce a deep impression on the minds of those who witness them, and to create a strong suspicion that these diseases are, under certain circumstances, contagious. Yet if such evidence as this be contrasted with incidents of an opposite kind, in which free communication has produced no such consequences, and be mixed up with the ordinary history of the diseases, the whole statement would produce little effect no indifferent persons-on cold judges like a committee of the House of Commons.

Few persons believe that consumption of the lungs is contagious; it is a question which requires for its solution long and well-used experience. A physician in early, and even in middle life, is an inadequate judge; but there are English physicians of the greatest experience, the highest eminence, and the least fanciful minds, who are convinced that this disease is sometimes communicated from a wife to a husband, or from a husband to a wife, during the long and close attendance which its lingering nature and strong affection sometimes occasion. It is an opinion, however, which he who entertains can never demonstrate to be true to him who rejects it; yet is it a reason for every precaution which does not interfere with the duties of the healthy to the sick.

In medicine, and all but the demonstrative sciences, there is often light enough to guide our conduct, when there is not enough to gratify our curiosity; and therefore it is that practical men are often compelled to act on evidence, which would sound unsatisfactory in the statement. There is no paradox in saying, that he who can give a striking reason for every measure which he adopts, is, for that very reason, a bad medical adviser; because he must neglect many which are necessary and useful, but the reasons for which at the outset are extremely obscure. cannot give a stronger instance of the difference between the evidence which is required to satisfy incompetent judges, and that on which physicians are often obliged to act, than that which is detailed in Dr. P. M. Latham's excellent Account of the Disease lately prevalent at the General Penitentiary.'

We

Having thus considered the signs by which we distinguish a contagious disease-the different degrees of clearness with which these signs show themselves-and the necessity there often is to

act

act on the supposition that a disease is contagious, although the evidence for it is far short of demonstration-we may now go on to consider whether these signs are discoverable in the history of the plague in a sufficient degree to make it proper for us to act with respect to it on that supposition. Now whoever will carefully examine the accounts of the plague transmitted to us by those who have witnessed its ravages, will find ample evidence of the following truths:-1st. That it is most liable to affect those persons who approach patients affected with it, and that in proportion to the nearness of the approach: 2dly, that those who avoid all intercourse with persons affected with the plague, generally escape the disease, and that in proportion to the care with which they avoid it. There are few facts indeed in medical history for which there is such a mass of evidence as these; or on which the experience of past and present times is so uniform. The most remarkable examples are afforded by the introduction of the plague into countries which had long been free from it, in consequence of intercourse with places in which it was then raging. The clearness with which this intercourse has been often traced is truly wonderful, considering the many temptations which travellers or mariners coming from countries infected with the plague have to clandestine intercourse. Of such histories there are so many on record, that the difficulty is which to select: we will begin with the plague at Marseilles, in 1720.

For seventy years the plague had never visited this maritime city, when, on the 25th May, 1720, a vessel sailed into the harbour, under the following circumstances: She had left Seyde, in Syria, on the 31st of January, with a clean bill of health, but the plague had broken out a few days after her departure, and she had called at Tripoli, not far from Seyde, where she took in some Turkish passengers. During the passage, one of the Turks died, after an illness of a few days. Two sailors attempted to heave the corpse overboard, but before they had time to do so, the captain called them away, and ordered it to be done by the comrades of the deceased. In the course of a few days the two sailors who had touched the corpse fell sick, and speedily died. Soon after this, two others of the crew, one the surgeon of the vessel, who of course had attended the sick, were attacked with the same symptoms, and died. These occurrences so alarmed the captain, that he shut himself up in the poop during the rest of the voyage. Three other sailors subsequently fell ill in the same way, were put ashore at Leghorn, and died there; the physician and surgeons of the infirmary certifying that their disease had been a pestilential fever. The vessel arrived at Marseilles, and the crew and cargo were landed at the lazzaretto. Soon afterwards, the

disease

disease (at first denied, but subsequently acknowledged to be the plague) attacked another of the crew-an officer put on board the vessel to superintend the quarantine-a boy belonging to the ship-two porters employed in unloading the merchandizeanother porter similarly employed-three more porters employed about the merchandize-the priest who had administered the last sacrament to the sick-the surgeon of the lazzaretto-and his whole family. Notwithstanding these events, the passengers, having performed a short quarantine of less than twenty days, were allowed to take up their quarters in the town, and to carry with them their clothes and packages. There were anti-contagionists in those days at Marseilles, as there are now in England, and this conduct was the result of their advice. When passengers after a voyage of nearly four months, and a quarantine of nearly three weeks, are at length let loose in a large city, their first employment is to roam about the streets; they have things to sell and to buy, and to see; they come in contact in the streets and in the shops with persons whom they think no more about, and who think no more about them. It is not surprizing, therefore, that the exact traces of the disease should soon be lost, and, that it should be often difficult, and even impossible, to follow it satisfactorily in every part of its progress. Of its origin and early advances in the town, the following account is given by M. Bertrand, a resident physician at Marseilles at the time..

'What is certain, is, that the plague was on board the ship of Captain Chataud; that it was communicated to the infirmary by the merchandize with which it was freighted; and that one of the first who fell sick in the city, had been passenger in the ship, and had only quitted the infirmary a few days, with his clothes and merchandize; and that among the very early victims of the distemper, were the family of a famous contraband trader, near the convent of the Carmes, and those of some other contraband traders, who resided in the Rue de l'Escale and its neighbourhood; that the suburb adjoining the Infirmary was attacked nearly at the same time with the Rue de l'Escale. I leave my readers to make the reflections naturally suggested by these facts.'

We pass over the terrific scenes which the subsequent progress of the plague occasioned in this ill-fated city; though they should be read by every one, if any such there be, who may have to legislate on this subject, and not be duly impressed with its fearful importance. We will not represent in detail the early doubts and obstinate denials that the disease was the plague; the fears of the magistrates to alarm the people; the unwillingness of the people to believe; their terror at its first announcement, and, after a short and deceptive calm, their drunken joy and mad confidence; the contests between the physicians and the magistrates; the in

sults

sults offered by the populace to the former; the scarcity of food; the bodies collected in the houses and in the streets, for want of persons to remove them; the fires lighted in the squares and market-places, and before the doors of every house, for the purpose of burning out the contagion, till the whole city was in a blaze; the flight of the people from the town; the immense graves; cart-loads of bodies tumbled into them in the utmost disorder; the shops and public places closed, and the deserted streets; all these form a picture which bewilders the mind by the number and horror of the objects; the mere recapitulation of them produces a sensation of giddiness and sickness.

But out of this confusion, we must select one or two incidents from which an inference may be drawn.

The Hôtel Dieu contained between three and four hundred foundlings of both sexes, besides the proper officers and attendants. At this hospital, a woman who had escaped from the Rue de l'Escale presented herself, stating that she was ill with a common fever. She was taken in and conducted to her bed by two maid-servants of the house; the next day the two maid-servants fell ill and died in a few hours. The day after, the matron, who, according to the duty of her situation, had visited the patient, fell ill, and died almost as suddenly. The disease spread with amazing rapidity; it destroyed all the children, together with every person belonging to the house-governors, confessors, physicians, surgeons, apothecaries, officers, servants; except about thirty, and even these took the infection, but ultimately recovered.

One of the greatest difficulties was the removal and interment of the dead. At first, carts had been hired to carry them away, and beggars and vagabonds were employed in the service. These soon fell, and those who followed them in their offices, soon followed them in their fate. The magistrates then applied to the officers of the gallies, praying for convicts to carry away the dead-this prayer was granted, and the convicts were promised their liberty if they survived. The first supply amounted to 133; these perished in less than a week. Another hundred were granted. In the course of six days they were reduced to twelve; and thus in less than a fortnight, out of 233, 221 perished.

An official report, transmitted to the Regent, stated that the physicians and surgeons of Marseilles unanimously declared, that when one person in a family was attacked and died, the rest soon underwent the same fate, insomuch that there were instances of families entirely destroyed in that manner; and if any one of an infected family fled to another house, the contagion accompanied him, and proved fatal to the family where he had taken refuge.'