MICHIGAN ACADEMY OF SCIENCE. 
149 
Tables showing colony counts on dilution plates. 
SERIES I. 
No. germs 
introduced. 
No. germs 
per c. c. 
in 24 hrs. 
No. germs 
per c. c. 
in 48 hrs. 
No. germs 
per c. c. 
in 72 hrs. 
No. germs 
per c. c. 
in 22 days. 
500 
4,000,000 
37,000,000 
23,000,000 
6,000,000 
226 
* 
38,000,000 
203,000,000 
116,000,000 
500 
86,000,000 
70,000,000 
37,000,000 
28,000,000 
+ 
226 
0 
0 
0 
0 
* Dilution too high. 
SERIES II. 
No. germs 
introduced. 
No. germs 
per c.c c. 
in 24 hrs. 
No. germs 
per c. c. 
in 48 hrs. 
No. germs 
per c. c. 
in 72 hrs. 
No. germs 
per c. c. 
in 6 days. 
5 
42,X)00, 000 
10,000,000 
21,000,000 
10,000,000 
199 
7,600 
6,000,000 
330,000,000 
700,000,00 
5 
18,000,000 
1,000,000 
4,000,000 
1,000,000 
+ 
199 
0 
0 
0 
0 
SERIES III. 
No. germs 
introduced. 
No. germs 
per c. c. 
in 2 4hrs. 
No. germs 
per c.c c. 
in 48 hrs. 
No. germs 
per c. c. 
in 72 hrs. 
No. germs 
per c. c. 
in 5 days. 
7 
87,000,000 
20,000,000 
11,000,000 
14,000,000 
86 
80,000 
125,000,000 
*2,000,000 
7,000,000 
7 
48,000 
7,000,000 
5,000,000 
2,000,000 
+ 
86 
0 
0 
0 
Q 
* Flask contaminated. 
