17 
It will be seen from this table that glycerin has practically no effect 
upon spores. They remain alive and virulent over two hundred days 
in u.lx percentages of glycerin at temperatures of 37°, 22°, and 10° C. 
The following series of tests were made to estimate more precisely 
the germicidal power of glycerin by counting the colonies from day 
to day and determining the rate of diminution. 
It will be seen from these studies that glycerin produces its greatest 
germicidal effect during the first twenty-four hours. The more resist- 
ing members of the colonies which survive this first period are able to 
resist the action of the gl 3 ^cerin much longer when they also finally 
succumb. 
STAPHYLOCOCCUS PYOGENES AUEEUS. 
The various percentages of glycerin (P.) mixed with distilled water were inocu- 
lated with a young culture of B. staphylococcus pyogenes aureus free of foreign organic 
matter and then each flask containing the test fluid was thoroughly shaken so as to 
make as uniform an emulsion as possible. The shaking was repeated each time 
before the fluid was withdrawn for the purpose of making the counts. 
One series of flasks was kept in the ice chest at 10° to 12° C. and another in the 
incubator at 37° C. 
The figures represent the number of organisms (i. e., colonies) per cubic centimeter. 
When 
counted. 
Distilled water. 
20 per cent glyc- 
erin. 
50 per cent glyc- 
erin. 
80 per cent glycerin. 
Pure glycerin. 
Incubator. 
Ice chest. 
Incuba- 
tor. 
Ice 
chest. 
Incuba- 
tor. 
Ice 
chest. 
Incubator. 
Ice chest. 
Incuba- 
tor. 
Ice 
chest. 
At once . . 
1 day . . . 
2 days... 
3 days... 
4 days. . . 
5 days 
4, 420, 000 
104. 000 
120.000 
3, 000 
1. 290. 000 
1.050.000 
408. 000 
920. 000 
110. 000 
88,000 
60, 000 
70. 000 
89. 000 
19.000 
28. 000 
22, 000 
15,000 
464, 000 
3,000 
253,000 
12,000 
-f 
64, 000 
1,000 
1,000 
66,000 
22,000 
12, 000 
2,000 
2, 500 
25 
4,200,000 
+ 
+ 
75 
3, 376, 000 
840, 000 
66, 000 
12, 000 
-1- 
-f 
-f 
-1- 
+ 
-1- 
+ 
6 days 
8 days 
12 days 
17 days 
22 days 
27 days 
31 days 
i 
When counted. 
Distilled water. 
50 per cent glycerin. 
Pure glycerin. 
Incubator. 
Ice chest. 
Incubator. 
Ice chest. 
Incubator. 
Ice chest. 
At once 
4, 060 
186 
1 
1 
/—Bouillon 
Agar 0 
—In bouil- 
lon 0 
0 
3,900 
140 
0 
fBouillon-p 
\Agar —0 
—Bouillon 
1 
—In bouil- 
lon 0 
0 
10,400,000 
110 
0 
0 
15, 750,000 
1,575,000 
630. 000 
126. 000 
1,395,000 i 
100 
25 ^ 
0 
3. 530.000 
1.200.000 
25,200 
Bouillon-t- 
Agar — 0 
-h Bouillon 1 
-FAgar (1) 
—In bouil- 
lon 0 
0 
1 day 
2 days 
3 days 
4 days 
—Bouillon 
0 
—In bouil- 
lon 0 
0 
37, 800 
—Bouillon 
0 
—In bouil- 
lon 0 
0 
5 days 
15, 900 
1,980 
542 
150 
83 
1 
0 
6davs 
7 dflya. . 
S fipys 
Q (inys 
if) (inysa 
12 days 
13 days 
1 
i 
a Left in room. 
6917— No. 16—03 2 
