28 LOSS THROUGH INSECTS THAT CABBY DISEASE. 
activity and prevalence of the common house fly is shown not only 
by repeated observations but also by an interesting plotting of the 
curve of abundance of flies in comparison with the plotted curve of 
abundance of death- from intestinal diseases, indicating that the 
test number of flies occurred in the weeks ending July 27 and 
August 3; also, that the deaths from intestinal diseases rose above 
the normal at the same time at which flies became prevalent, culmi- 
nated at the same high point, and fell off with slight lag at the 
time of the gradual falling off of the prevalence of the insects. 
Similar studies have beeu carried on during the summer of L908 
in the city of Washington, and the curve of typhoid-fly abundance 
for the whole city, as well as that for a district comprising eight city 
squares in which intensive studies have been made both of flies and 
i f disease, will be plotted at the close of the season. At the time 
of present writing this work has not been completed. 
The typhoid fly also possesses importance as a disseminator of the 
bacilli of tuberculosis. In a paper by Dr. Frederick T. Lord, of 
Boston, reprinted from the Boston Medical and Surgical Journal for 
December 15, 190i. pages 651-654. the following conclusions are 
reached: 
" 1. Flies may ingest tubercular sputum and excrete tubercle ba- 
cilli, the virulence of which may last for at least fifteen day-. 
*• 2. The danger of human infection from tubercular flyspecks is 
by the ingestion of the s'pecks on food. Spontaneous liberation of 
tubercle bacilli from flyspecks is unlikely. If mechanically dis- 
turbed, infection of the surrounding air may occur. 
"As a corollary to these conclusions, it is suggested that — 
" 3. Tubercular material ( sputum, pus from discharging sinuses. 
fecal matter from patient- with intestinal tuberculosis, etc.) should 
be carefully protected from flies, lest they act a> disseminators of the 
tubercle bacilli. 
" 4. During the fly season greater attention should be paid to the 
screening of rooms and hospital wards containing patients with 
tuberculosis and laboratories where tubercular material is examined. 
" 5. As these precautions would not eliminate fly infection by 
patients at large, foodstuffs should be protected from flies which may 
already have ingested tubercular material." 
From all these Pacts it appears that the most important part played 
by the typhoid fly or house fly in the human economy is to carry 
bacteria from one place to another. The following table and com- 
ments are taken from Bulletin No. 51 (April. 1908), of the Storrs 
Agricultural Experiment Station. Storrs, Conn., entitled " Sources of 
Bacteria in Milk," by W. M. E>ten and C. J. Mason: 
