QUARANTINE. Quarantine regula tions are regulations, chiefly of a restric tive nature, for the purpose of preventing the communication from one country to another of contagious diseases, by means of men, animals, goods, or letters. The term quarantine originally signified a period of forty days during which a per son was subject to the regulations in question. The period of forty days du ring which a widow entitled to dower can remain in her husband's mansion house after his death is also called, in our law, the widow's quarantine. (Black stone's Commentaries, vol. ii. p. 135.) Quarantine regulations consist in the interruption of intercourse with the coun try in which a contagious disease is sup posed to prevail, and in the employment of certain precautionary measures re specting men, animals, goods, and letters coming from or otherwise communicating with it. Men and animals are subjected to a probationary confinement, and goods and letters to a process of depuration, in order to ascertain that the contagious poison is not latent in the former; and to expel it, if it be present, in the latter. Quarantine regulations respecting men and animals are therefore founded on the assumption that the contagious poison; after having been taken into the constitu tion of a man or an animal, may remain dormant in it for a certain time, and that a seclusion of a certain duration is neces sary in order to allow the disease time to I show itself, or to afford a certainty that the disease is not latent. Quarantine regulations respecting goods and letters are founded on the assumption that the contagious poison may be contained in and letters, and transmitted from as to communicate the disease to men.
The country from which the introduc tion of a contagious disease is appre hended, may either be conterminous with the country which establishes the qua rantine regulations, or may be divided from it by the sea. Accordingly qua. rantine lines may either be drawn round a coast, as is the case in France, Italy, and Greece, with respect to the Levant, or they may be drawn along a land frontier, as on the frontier between Aus tria and Servia and Wallachia.
The contagious diseases which qua rantine regulations are intended to guard against are plague and yellow-fever, and latterly cholera.
The principal disease, with reference to quarantine regulations, is the plague of the Levant ; and in practice quarantine regulations are of little importance ex cept with respect to the intercourse by land and sea with Turkey, Asia Minor, and Egypt, and some other of the Mo hammedan countries bordering on the Mediterranean.
The disease styled plague, although formerly prevalent over the whole of Europe, is now nearly confined to the Le vant; but its symptoms, morbid changes, history, and mode of propagation, bear so close a resemblance to those of the malignant typhus of this country, that it is difficult to regard them otherwise than as different types of the same disease. The plague of the Levant appears like wise to be generated by the same causes which generate typhus in this country, namely, filthy, crowded and ill-ventilated dwellings, want of personal cleanliness, defective drainage, and insufficient or un wholesome food. We believe it to be certain that, when the disease has been thus generated, it may, particularly under the influence of any of the causes which originally produced it, be communicated from one person to another. It seems likewise that its communication from cne person to another is promoted not only by filth, want of ventilation, and the other usual accompaniments of squalid po verty, but also by certain atmospheric causes, such as a certain state of heat, moisture. &c., respecting which we are as yet imperfectly informed. The plague therefore is both epidemic and contagious; that is to say, it may either be generated by local causes, which simultaneously affect a large number of the inhabitants of a country, or it may be communicated directly from one person to another. Where a disease is both epidemic and contagious, it is difficult to determine what proportion of the cases of it are due to local causes and what proportion to contagion. The analogy of typhus in this country would lead us to believe that the number of cases of plague in the plague countries produced by contagion is small as compared with the number pro duced by local causes. The invisible nature of the ordinary causes of plague and other epidemic diseases, and the sim ultaneous seizure of many persons in the same district, the same street, or the same house, have naturally led to the belief that the disease is in every case communi cated from one person to another ; ac cording to the fallacy ingeniously exposed by Dr. Radcliffe, who, on being asked his opinion respecting the contagiousness of epidemic diseases, answered : " If you and I are exposed to the rain, we shall both be wet; but it does not follow that we shall wet one another." This view of the ordinary causes of plague is likewise confirmed by the un doubted fact that the poor are the chief sufferers by it, and that it prevails most in the filthiest and worst quarters of towns.