19141 
NOLTE— SALIVARY ORGANISMS AND AIR POLLUTION 40 
tion are the ones to be considered in this investigation. They 
doubtlessly constitute an important means whereby patho- 
genie organisms enter the air from an infected person, subse- 
quently to be transmitted to other individuals. 
The discharge of sputum furnishes the most obvious way 
whereby pathogenic organisms may be expelled from the mouth. 
The expectorated mucus dries, and, in the form of dust, may 
later be inhaled to produce infection. Тһе work of Flügge 
and members of his school; however, has drawn attention 
to а more direct and по less important way by which germs may 
be aérially conveyed from the mouth. Тһе problem of trans- 
mission of micro-organisms by means of particles of mucus 
expelled from the mouth in various expiratory acts, was attacked 
in two ways by the investigators referred to above: 1. Тһе 
mouth was artificially infected with a culture of Bacillus pro- 
digiosus. This organism was chosen because the red pigmenta- 
tion of the colonies renders the identification easy. After agar 
plates had been placed at various distances from the person 
being experimented upon, the individual proceeded to speak, 
cough, sneeze, etc. At the end of the experiment the agar 
plates were covered and incubated at 25? C. for 3 days, during 
which time the characteristic red colonies of B. prodigiosus 
made their appearance. Тһе possibility of error due to the 
previous presence of this organism in the air of the room was 
excluded by exposing a series of agar plates immediately before 
the experiment began, with the result that in all cases the 
organism failed to appear. Тһе length of time that droplets 
of mueus remained suspended in the air after the several expir- 
atory acts was determined by exposing plates at various periods 
after the experiment had been completed. 2. Glass slides or 
empty Petri dishes were placed at various distances from a 
tubereular patient. Тһе droplets of mucus expelled during 
coughing, and deposited upon the glass slides, etc., were either 
examined microscopically or were washed off and injected 
intraperitoneally into guinea-pigs. In the former case a bacillus 
giving the characteristic staining reaction of the tubercle 
bacillus was found, and in the latter the development of tuber- 
1 Gordon, loc. cit. 
