108 BOTANICAL GAZETTE [AucU 
SERIES I. SODIUM CHLORID 4 
There were prepared sixteen Erlenmeyer flasks (125°° capacity), 
each containing 50°¢ of solution, made up as follows: The first flask 
contained 50°° of 1 per cent. peptone solution in distilled water; the 
second contained a 0.1 m solution of NaCl and 1 per cent. peptone; 
the third flask contained 0.2 m NaCl and 1 per cent. peptone; and 
so on, the concentration of NaCl increasing by 0.1 m in each succeed- 
ing flask up to the sixteenth, which contained 1.5 m NaCl and 1 per 
cent. peptone. All the flasks were plugged with cotton, sterilized in ” 
the autoclave at a pressure of 1.25 atmospheres, and when cool were 
inoculated from a culture of B. subtilis in the manner above described. | 
After two days’ incubation at 28° to 29° C., the ammonia formed in” 
the peptone solutions was distilled off and determined as above | 
explained. Table I shows the results. ; 4 
Plotting a curve by laying off the con 
TABLE I centrations as abscissae and _ the milli 
a we caus grams of N (as NH,) as ordinates (jig. 1); ’ 
gent tenths ™ | formed as NH, | We note the following: NaCl up to a con-_ 
% wae centration of o.1 m stimulates B. subtilis” 
: ati as an ammonifier, but beyond that con” 
3 2.80 centration it becomes gradually more — 
“ be and more toxic, and at 1.3 m we find” 
6 2.38 scarcely any ammonification. It is evr 
8 tf dent, also, that NaCl is not nearly a_ 
2 ee toxic for B. subtilis as it has been found — 
it 1.05 by Logs (8, p. 412)' and OsTwALD (21) 
be aes to be for animals, and as OsTERHOUT 
i: — (17) and MacGowan (14) have found it : 
to be for plants. Lors found, for 
stance, that the formation of embry 
in the eggs of Fundulus was rendered impossible in a 0.625 m 
placed in a 0.0937 m solution of NaCl usually died within a few mi 
t See also § and literature there cited. : 
