It appears from the researches of eminent writers, that this disease, as also the measles, had prevailed in China and Hindostan from remote antiquity, yet had not extended to the more western nations until the middle of the sixth century. About this period these maladies reached the southern coast of Arabia, by vessels trading with India, and broke out near Mecca, during the war of the elephant, (as it has been termed), in the year 569, immediately before the birth of Mahomet.

During the latter parts of the sixth, and the whole of the seventh century, they were spread by the Arabians over the remaining countries of Asia, and all that part of Africa which is washed by the Mediterranean Sea. In the eighth century Europe was contaminated, in consequence of the Saracens invading Spain, Sicily, Italy, and France, and the above diseases gradually extended to the north. They had reached Saxony, Switzerland, and England in the ninth or tenth century. And lastly, in the beginning of the sixteenth century, twelve years after the death of Columbus, the infections were transported by the Spaniards to Hispaniola, and soon afterwards to Mexico, and diffused speedily over that country also. And in every country where it was introduced, it caused fearful destruction.

At length the practice of inoculation for the disease found its way to England. When or where the practice originated is involved in obscurity. It is said the method had been practised by the Brahmins of India, "time out of mind." In 1713 Dr. Emanuel Timoni, an Oxford graduate, who had settled at Constantinople, wrote to Dr. Woodward in London, giving an account of the new process, and testifying to its success.

Some letters of Dr. Williams, Mr. Owen, and Mr. Wright, in the Philosophical Transactions for the year 1722, assert that inoculation was well known in the south of Wales at that time, and had been of long standing. It seems likewise to have been practised in the Highlands of Scotland before it was practised in England. It was first introduced into England from Turkey, by Lady Mary Wortley Montague, about the year 1721, whose son was inoculated in Constantinople during her residence there, and whose daughter was the first person inoculated in England. Next, the daughter of a Doctor Keith, who had visited Miss Wortley. Next, six criminals, who were pardoned on condition of their submitting to the experiment (and who all recovered), and, at length, in the year 1726 on some members of the Royal family. But it was some years before the practice became general.

The great advantages of inoculation were, that from being enabled to put the patient in a favourable state of health to receive the infection, the disease was usually much milder, and the fatality very much less; so that although the proportion of deaths among those who took the disease naturally was one in three, amongst those who were inoculated the proportion was not more than one in three hundred.

The late Dr. Thomas said: "Although inoculation for the Smallpox may have been beneficial to individuals, by greatly lessening the chance of death, yet it may safely be asserted, that it has proved of no benefit to the community at large, but the reverse; which is evident by the bills of mortality, as they clearly prove that the disease of Small-pox has increased in England since the introduction of inoculation, in the proportion of 19 in every 100."

Since the introduction of vaccination in England, laws have been passed making inoculation penal, but there are to be found in every community some persons who take a delight in setting the law at defiance; and who cling to inoculation, and do all in their power to prevent the extermination of the disease.

It may occasionally happen that, under peculiar circumstances, inoculation may be justifiable, where a person has been exposed to the infection, who has not been vaccinated, and where no vaccine lymph is obtainable. The following circumstance, related by a naval officer to Professor Gregory, is an example: "The Smallpox was introduced among the crew of a man-of-war, in a tropical climate, where no vaccine matter was to be procured. The men were almost all unprotected, (had neither had Small-pox, nor been vaccinated). Sixteen of them took the disease in the natural way; and of these nine, or more than one half, died. Of 363 who were inoculated, under the disadvantage of a hot climate, and no preparation, not one perished.

In the inoculated disease the period of incubation is comparatively short; the pustules are seldom numerous, and still more seldom confluent; and the secondary fever is generally slight or wanting.

Mr. Marson, who has been the resident surgeon to the London Small-pox and Vaccination Hospital for the last thirty-four years, says: "Natural Small-pox is a most fatal disease at all periods of life; the most so in infancy and advanced life; the least so from 10 to 15 years of age; under 5 years it is 50 percent.; still greater, however, under two years; the mortality after the age of twenty rises suddenly, and increases gradually; at 30 it exceeds the mortality of infancy; and after sixty hardly any escape.

The disease has always been known to be exceedingly fatal among the North American Indians. There has lately been a great outbreak of Small-pox in England, which will have the effect of making vaccination for the future more carefully attended to than it has been.

Mr. Marson "has always made it an imperative rule that every nurse and other servant of the Hospital should, on entering the service, be vaccinated. In their case it is generally re-vaccination; and it is never afterwards repeated. These nurses live in the closest daily and nightly attendance upon Small-pox patients; and the other servants are constantly exposed to the profuse contagion; yet in no single instance, during these thirty-four years, has any one of these servants and nurses been affected with Smallpox. Surely no stronger proof than this can be imagined, that re-vaccination in the adult is an absolute protection against Smallpox, and need not be repeated."