1914] 
. NOLTE—SALIVARY ORGANISMS AND AIR POLLUTION 57 
small the extent of the liquefaction after 30 days' growth at 
20°C., was the same with any one organism. 
In the study of the action on sterile certified milk ее 
attention was paid to the coagulation of the milk and to the 
production of acid. Observations were further made on the 
effect of the organisms on lactose, saccharose, mannite, salicin, 
inulin, sorbite, raffinose, and rhamnose. Тһе medium in which 
these organic substances were used was prepared according 
to Dr. Houston’s formula, as follows: 
Liebig’s beef extract 1.0 per cent 
Peptone 1.0 per cent 
Organic compound to be tested 1.0 per cent 
Sodium bicarbonate 0.1 per cent 
10 per cent litmus solution 1.0 per cent 
The medium, neutral in reaction to litmus, was sterilized for 
15 minutes at 15 pounds pressure in 500 cc. containers, from 
which sterile fermentation tubes, provided with glass caps, 
were directly filled. In doing this it was necessary to take 
utmost precautions to obviate any possibility of contamina- 
tion. The various organie media thus prepared were inocu- 
lated, not from an agar slope, but from a 48-hour broth culture. 
Gas formation and the production of acid in the several media 
were observed after 3 days’ incubation at 37°C. 
DISCUSSION OF RESULTS 
A thorough study of the results will now be made with a 
view of finding, if possible, some characteristic or group of 
characteristics, morphological or biochemical, which may be 
used in differentiating the salivary cocci from the coccus forms 
of the air and the skin. 
The cell grouping varies throughout, there being no arrange- 
ment characteristic of any particular group. As observed, all 
the forms occur in groups, chains, and pairs. As regards the 
deportment of the various organisms toward the Gram stain, 
it was noted that all of the salivary cocci gave a positive reac- 
tion in both tests; of those from the air, 3 were positive in 
the two tests, 8 alternately negative and positive, and 6 negative 
throughout; of the skin cocci, 4 were positive and 2 negative 
