Variola: Pox. 335 



pox have usually extended from the east, and the disposition has 

 been to refer its origin to the crowded communities of central 

 Asia, but nothing is certainly known as to such origin and the 

 lack of definite recognition and description cannot be taken as 

 implying that the disease did not exist. The extension of small 

 pox to America in 1520 was distinctly traced to a sick negro 

 slave landed in Mexico, and the way in which it swept the con- 

 tinent killing the Indians by tens of thousands, speaks strongly 

 for its prior absence and the extraordinary susceptibility of the 

 hitherto unaffected Indian races. 



The variolae of animals are not recorded until later, the mild- 

 ness of the forms attacking cattle and horses, and the lack of 

 close observation of the diseases of sheep furnishing a reasonable 

 explanation. . We must pass over as uncertain the lues ovium of 

 Thomas Wallsingham, (Historia Anglicana), imported in a rotten 

 Spanish ewe in 1274, and which prevailed for 25 years destroy- 

 ing nearly all the sheep of the kingdom, also the reference to the 

 "pockes" of sheep in Chaucer's "Pardoners' tale" as highly un- 

 certain. I^aurent Joubert in his work on the "peste" mentions 

 sheep pox as prevailing in 1567, and Rabelais speaks of it as pre- 

 vailing in France in 1578. It prevailed in Padua in 1649, in 

 Venice in 1664, 1672, and 1674 (Bottani), in Italy in i6go 

 (Ramazini), in Germany in 1687-8 (Stegman), in England in 

 1711, in Hungary in 1712, in France, Italy, etc., in 1714 (Kanold), 

 in Venice and Bohemia in 1719 (Bottani), in Saxony in 1720, 

 in Venice and France in 1723-24 (Bottani, Astruc), in Thurin- 

 gia in 1725, in Siberia in 1771 (Pallas), and in Persia generally 

 at the beginning of the 19th century (Bruce). Great Britian, 

 long protected by her insular position, was infected by sheep 

 from Germany in 1847 and again in 1862. Under ovination the 

 first invasion prevailed for four years causing wide spread 

 destruction ; under strict separation based on thermometry, the 

 second lasted but four months. 



Cowpox has existed in England for centuries, but it has only 

 attracted general attention since the introduction of vaccination 

 by Jenner in 1796. Horsepox has existed concurrently with cow- 

 pox, the infection being habitually transferred by the hands of 

 the milkers from horse to cow and vice versa. Jenner found it 

 so common in the Valley of Gloucester, that he considered it as 



