Armstrong – Table of Contents

2). It seemed probable that the measures of suppression as applied during the epidemic of
1918 were partially successful at Kelleys Island, where, the authors admitted, conditions
were rather ideal for such procedure.
3). Milk and water had no apparent relation to the spread of influenza upon the island in
1920.
4). The apparent influence of crowding, housing conditions, economic status and general
sanitation seems to have been exerted in opposite directions during the two epidemics
(1918 and 1920).
5). The incubation period most frequently observed appeared to have been from 1 to 4
days.
6). A relative immunity seemed to be apparent 15 months following the 1918 epidemic.
Armstrong and his associate, Ross Hopkins, thus using a strictly epidemiological
approach without laboratory support, were able to trace the course of an influenza
epidemic in an isolated community and derive meaningful conclusions. It is apparent that
they accumulated massive amounts of data from the 689 persons with which to construct
the charts, tables and maps that appeared in the manuscript. In the 1920’s, this
accumulation of data represented a labor-intensive effort since the authors did not have
the benefit of calculating machines or of late 20th century computers. In recording the
data for tabulation, they might have had available punch cards that could be manipulated
by hand with a thin metal stylus and a special type of punch. The cards were about 8 or
more inches square with a double row of perforations on each side. A master index card
contained the key to the data that was being studied. The punch could remove one or two
perforations depending on the depth of the cut, and the removal of these perforations