1893. Bacterial Flora of the Atlantic. 413 
Ineach case a marked reaction was noted, showing that 
the nitrate solution had been reduced and that nitrites were 
present in varying amounts. After four days’ incubation at 
35°C., the cultures were analyzed quantitatively for U as nit- 
rite by colorimetric standards with the following results: 
Total am’t of N as KNO in culture solution, 14.00 parts in 100,000, 
Nas KNO, in culture of Bacillus limico a 20 ee " 
ss ‘ e a y a = pelagicus, 2.8 
pr oie Sb maritimus, 2.1 
‘* = RF litorosus, 2.3+4+ ‘ 
This indicates that the amount of nitrogen converted into 
nitrite from nitrate as a result of four days’ growth of bac- 
teria is by no means inconsiderable; in one case, B. pelagicus, 
reaching one-fifth of amount available. The marked difference 
0 be noted in the amount reduced by B. limicola and B. litor- 
“sus is not to be explained by the difference in the rapidity 
growth but is due to relative differences in reducing pow- 
fs, At 35°C., B. litorosus grows much more slowly than at 
me ordinary temperature of the room, while the reverse is true 
OB. limicola. This relative difference in rate of development 
_ Showever in inverse ratio to the amount of nitrogen reduced 
S shows that the denitrifying ability of the two germs dif- 
toa considerable degree. 
In order to determine whether the reduction process is car- 
E °n until free N or NH,OH is produced, another cul- 
€test was made. The production of NH,OH from nitrate 
ti be recognized by nesslerization as it is impossible to 
nguish between NH,OH that might come from the or- 
a rehy in the peptone and that from the nitrate or nitrite, 
ba using a known amount of nitrate as a culture patie 
ibiene determining the amount present at the ee We 
Percents. © 18 able to ascertain whether any considera 
ntage has been reduced. 
a oma Solution of NaNO, was made, to which oe 
ture fart dry peptone was added. This was used as oh ro 
& to age _ cultures of the several forms eas ee a0 
Petiod of ae of nitrite present after they had incubate ar 
but in vedays. Growth of germs was evident in cu 
itrit, ° CaSe was there any diminution of the amount 0 
‘Vera] €nt, so the conclusion was evident that while the 
hits. PeCies here described able to reduce nitrates to 
E Mites, the | escribed were ab ae 
| BSeous Ny ater stages of the reduction process 0 
Were not carried on by these forms. 
