of intercourse, he observed, "that the Small Pox "was seldom to be met with, and when it oc"curred, its progress was always checked by "the vigilance and terror of the natives."

Since Mr. Saunders noticed, that this disease was rare in the present times, it probably had been much rarer in the early ages of the world. For the mutual intercourse and aggregation of mankind augment as they recede from barbarism; and infectious diseases would naturally be less frequently epidemic, and less destructive among hunters and shepherds, than among men in a more advanced state of society.

The Small Pox was in fact so rare in the 16th and 17th centuries, on the western coast. of Hindostan, and in the islands of Ceylon and Java, that some of the Portuguese navigators believed that no such disease had ever existed there; and the Dutch navigators were ignorantly accused of having transported this disease to countries *, in which prayers and offerings had been instituted, to deprecate its fury,

Navigatio ac Itinerarium I. Hugon. cap. 34. Hage, 1599. Ephemerid. de l'Acad. des Curieux. Dec. 1. an. 9. 10. 1678 and 1679. Histoire de la Mission Dannoise, dans les Indes Orientales, tom. i. p.42. Traité des Maladies des Femmes, tom. iv. p. 177.

at a period when Holland was an uninhabited marsh.

The dread of the Small Pox, and the strong measures adopted in the East to controul it, may be considered as causes which contributed to prevent this infection from extending westward. But, undoubtedly, the principal cause was the peculiar situation of the regions through which this infection was diffused, separated from the rest of the world by deserts, and by the ocean. Yet neither these barriers formed by nature, nor any defences fabricated by man, have preserved any country from foreign hostile intrusion. Whether the expeditions of Bacchus and Sesostris into India be true or fabulous, are themes for antiquarians, but the invasions of India by Darius the son of Hystaspes, and by Alexander, are certified by history and the Small Pox does not appear to have been carried back into Persia by either. This was a calamity more likely to have been effected by an irruption, than by an invasion: but the industrious Chinese, and the unambitious East Indians never thought of quitting their homes, to break into the territories of their neighbours.

The rapacious invaders who went from Persia, would of course be attacked by the diseases which prevailed in the countries they laid waste: but the numbers which perished, the time which was spent in so distant a warfare, and the ex

tent of the deserts which were re-crossed, ap. pear to have secured their native country from being contaminated by the few survivors of those expeditions.

Scylax, who commanded the army of Darius is said by Herodotus, to have spent two years and a half in his progress down the Indus to the Arabian gulf. The handful of men who escaped back to Persia, would probably be cleared by that time, of all contagion from Small Pox, even if that malady had ever infected their camp.

Alexander the Great, after crossing the Indus proceeded eastward to the banks of the Hyphasis, the modern Bryah. He was there stopt by a mutiny of the army, and forced reluctantly to return to the Hydaspes.

There a fleet was equipped with which he resolved to proceed down the Indus to the ocean. Such a leader, with thoroughly experienced officers, would certainly take every precaution in their power, to preserve the health of the troops, and to hinder infectious maladies from spreading through the army; and nine months were exhausted before they reached, with diminished forces, the mouth of the river. The army was then divided; one portion proceeded by sea under the conduct of Nearchus; and Alexander marched to the west with the re

mainder, through a desert and almost uninhabited country.

Arian mentions, that the sufferings of the army were dreadful, that the beasts of burden perished, and the sick were necessarily abandoned. Plutarch declares †, that from bad diet, excessive heat, and violent diseases, three fourths of the army perished. Quintus Curtius asserts, that when the army were encamped near the mouth of the Indus, "a scab + "attacked the bodies of the soldiers, and spread

by contagion." He dwells with eloquence on the miseries which the army endured from famine, diseases, and pestilences, in a march of sixty days, through a horrid country, part of which resembled a wilderness. As no food was to be found even for the beasts of burden, they all perished; the sick, unable to proceed, in spite of their entreaties, were left to starve; while the remaining troops hurried forward to reach a cultivated country. Certainly there is little likelihood that those afflicted with the Small Pox could survive such hardships.

*Arian. Hist. Ind. cap. 25.

+ Plutarch. The Life of Alexander.

Quint. Curt. cap. 10. "Quippe scabies corpora invasit, "et contagium morbi etiam in alios vulgatum est." It is possible that this was the Small Pox ill described.

Nearchus the admiral, who conducted the maritime expedition, was too experienced an officer to suffer any persons to embark, who were known to be contaminated with an infectious disease. But if from inadvertence this should have happened, as the coasting voyage lasted seven months, there was ample time to get rid of the contagion.

When all the circumstances of that frantic enterprise are considered, it will not excite wonder, that the wreck of the Macedonian army did not consummate their misfortunes, by bringing the Small Pox into Persia.

But as the valuable productions, and the curious manufactures of China and India were early coveted and transported to the more western nations, it is more surprising that the infection was not communicated by commercial intercourse. This certainly would have occurred very early if those countries had not been separated in so remarkable a manner from the rest of the habitable world.

Commerce with those nations by land, was only practicable by means of the camel, whose powers of enduring heat and thirst, without drinking for ten days, enabled the merchants to convey their goods across the sandy deserts. But we may safely conjecture, that no person