668 SUPPLEMENTARY APPENDIX. 



statements in various medical and other writings. There seems, how- 

 ever, to be adequate proof of the prevalence of small- pox in the East, 

 in Asia Minor and other countries, even in the earlier centuries of the 

 Christian era. 



A view very generally taken teaches that small-pox, introduced from 

 the East, began to be common in western Europe during the fifteenth 

 century, though perhaps existing still earlier; that, it increased during 

 the sixteenth and seventeenth centuries, especially the latter ; and that it 

 was very prevalent during the eighteenth century. 



In dealing with the eighteenth century it must be borne in mind that 

 during the second half of the century the natural conduct of small-pox, 

 as we shall see later on, was modified by the practice of inoculation — that 

 is, by the artificial giving of the disease by the introduction of the virus 

 through a wound in the skin. 



Our knowledge of the history of small-pox in western Europe during 

 the seventeenth and eighteenth centuries is very largely based on the 

 of&cial records known as the '' London Bills of Mortality.'' Official 

 records bearing on small-pox are furnished by Geneva, going back as 

 far as the sixteenth century, by Sweden, going back to the year 1749, 

 and by some other places. Data are also furnished, especially' for the 

 latter part of the eighteenth century, by parish records in. various parts 

 of Great Britain reaching over a variable number of years, as well as by 

 scattered statements in various works. 



These Bills of Mortality form by far the most complete source of our 

 knowledge of small-pox in England in past times ; but it must be borne 

 in mind that in respect to any contagious disease like small-pox the 

 conditions of London were peculiar. The population was to a marked 

 extent a moving one ; a large number of persons were continually 

 entering London or leaving it, were passing to and from it, from and to 

 the provinces of England and other countries. Of these persons, some, 

 coming from infected districts, brought into London fresh sources of 

 contagion ; others again, coming from districts free from small-pox, and 

 never having had the disease, brought into London fresh material to serve 

 as food for the disease. Further, London presented in an exaggerated 

 degree the two features of a great city which have a great influence on 

 the progress and characters of a contagious disease like small-pox. The 

 crowding both of the dwelling-places and the thoroughfares, as well as 

 the movement continually going on, multiplied the opportunities for the 

 spread of disease, and the accompanying insanitary conditions, as well as 

 the greater inducement to irregular living, tended to increase the severity 

 of the disease when taken, and to heighten the mortality from it. The 

 history of small-pox in London must not be taken as representative of 

 the history of small-pox in England generally. 



Inoculation of Small-pox. 



The practice of inoculation for the small-pox — that is, the artificial 

 introduction of the virus into the system by the insertion of fluid from 

 a variolous pustule into wounds of the skin made for the purpose — 

 began definitely in England towards the end of the first quarter of the 



