[Yon 1 
56 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
This author uses as а basis the solar spectrum with its six 
fundamental colors and intermediate hues, augmented by a 
series between violet and red not in the spectrum. 
BIOCHEMICAL REACTIONS 
The production of indol was investigated in 5-day peptone 
broth cultures incubated at 37°C. One cc. of a 10 per cent 
sulphuric acid solution was thoroughly mixed with the broth 
culture, and then 1 сс. of a freshly prepared 0.01 per cent 
solution of sodium nitrite was carefully run in on top of the 
mixture. The appearance of a pink ring at the juncture of 
the nitrite solution with the acid-peptone solution, was regarded 
as an indication of the presence of indol. A blank determina- 
tion for purposes of comparison was made in each case. The 
action on neutral red broth as regards change in color was 
observed in cultures incubated for 5 days at 37°C., in the 
presence of hydrogen. 
The organisms were further grown in solutions of nitrate 
broth to determine whether or not reduction takes place, and 
if so, whether to nitrite or to ammonia. In carrying out the 
test a tube of nitrate broth was inoculated with the organism. 
to be tested, and incubated for 4 days at 37°C., an uninoculated 
tube of nitrate broth being similarly treated to serve as a check. 
At the end of 4 days, 3 cc. of the broth were removed to a clean 
test-tube, and 2 cc. each of a naphthylamine solution and of а 
sulphanilie acid solution added. Тһе development of a red 
color indicates the presence of nitrites, the intensity of the 
color being proportional to' the amount of nitrites present in 
solution. То test for ammonia in the remaining portion of 
the culture, а few drops of Nessler's solution were added. 
The appearance of a yellow color or precipitate indicates the 
presence of ammonia. Іп studying the liquefaction of gelatin 
by the cocci under observation, the extent of the action 
only was determined. This was accomplished by spreading 
а suspension of the organism over the surface of gelatin in 
10 mm. tubes. It was found that the amount of material used 
in this inoculation did not affect the total amount of liquefaction, 
ie. whether the amount of transferred material was large or 
