518 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
LANDMARKS IN THE DEVELOPMENT OF PREVENTIVE MEDICINE 
The only practices of the ancients which we at this day may 
consider to be preventive measures based upon a firm, rational 
foundation as we understand the subject, are found described in 
the Mosaic law. All other practices of the ancients designed to 
prevent diseases are clearly allied with religion and superstition, 
and hence were of little importance and no value. Therefore the 
Mosaic instructions when interpreted in the light of present-day 
knowledge have an immense importance. ‘These practices, however, 
do not seem to have been copied by contemporaneous Gentile races. 
Aside from the foregoing the earliest public-health practice which 
has survived to the present day is maritime quarantine, which was 
developed by the medieval Italian cities of Venice and Genoa when 
at the height of their commercial splendor as a protection against the 
introduction of plague from oriental ports. At this time the 
ideas of disease transmission were very vague, but a suspicion of the 
transmissibility of some seems to have existed. A little later, in 
1546, Geronimo Fracastorius published in Venice a work entitled 
“De contagionibus et contagiosis morbis et curatione ” in which was 
first definitely advanced the doctrine of contagion. He divided in- 
fections into three classes: (1) Those infecting by immediate con- 
tact, (2) those infecting through intermediate agents, such as fo- 
mites, and (3) those infecting at a distance or through the air. 
In 1659, Kircher, and, in 1675, van Leeuwenhoek first observed and 
described living organisms too small to be seen by the naked eye. 
Kircher in 1671 suggested that various infections were the result of 
the activity of these minute organisms. Jircher’s views were re- 
ceived with skepticism by his contemporaries, and later, in 1672, 
Plenciz of Vienna again advanced the same views. These theories, 
however, did not gain headway until the following century, when 
they were demonstrated scientifically. 
‘The first attempt at artificial active immunization among Euro- 
pean nations must be credited to Lady Mary Wortley Mon- 
tague, who, from 1717 to 1721, introduced into England from Con- 
stantinople the process of variolation as a protection against small- 
pox. This was an event whose importance has been overshadowed 
by the employment of an attenuated virus for the same purpose by 
Jenner. His discovery was first published in 1798. 
In 1843, Oliver Wendell Holmes, an American physician and 
author of note, first called attention to the contagiousness of puer- 
peral fever. The activity of water as a route for the transfer for 
infective agents was first recognized, in 1854, by Doctor Snow in 
connection with the famous Broad Street well cholera outbreak. 
Three years later Doctor Taylor recognized the similar activity of 
