78 
' Experiment Xo. 54. 
B. dijsenterise. 
Culture, ‘‘Shiga;” forty-eight hours’ giwvth in ^yhole milk that had been sterilized 
by the fractional method three days. Reaction. 0.27 per cent acid.. 
The milk at 21° C. immersed in constant-temperature water bath at 00° C. 
1 
Milk culture. \ 
At start 
2 minutes after immersion 
minutes after immersion 
3j minutes after immersion . . . 
4J minutes after immersion. . . 
oj minutes after immersion. . . 
61 minutes after immersion. . . 
71 minutes after immersion. . . 
91 minutes after immersion . . . 
141 minutes after immersion... 
Temperature. 
(°C.). ' 
; 1 c. c. milk 
: culture in 
j bouiUon. 
21 
. ' Growth. 
55 
Do. 
57 
Do. 
59. 
Do. 
60 
Do. 
1 minute at 60. . . 
Do. » 
2 minutes at 60. . 
Do. 
3 minutes at 60 . . 
Do. 
5 minutes at 60 . . 
Do. 
10 minutes at 60 . 
No growth. 
Experiment Xo. 55. 
B. dysenteri^e. 
Culture, ‘‘DuA-al;” forty-eight hours’ growth intvhole milk that had been sterilized 
by the fractional method three days. Reaction, 0.306 per cent acid. 
The milk at 21° C. immersed in constant-temperature water bath at 60° 
Milk culture. 
^ Temperature. 
(°C.). 
1 c. c. milk 
culture in 
bouillon. 
At start 
21 
Growth. 
2 minutes after immersion 
. . . 55 
Do. 
21 minutes after immersion 
57 
Do. 
31 minutes after immersion 
59 
Do. 
5 minutes after immersion 
60 
Do. 
6 minutes after immersion 
1 minute at 60 
Do. 
7 minutes after immersion 
2 minutes at 60 .. . 
Do. 
8 minutes after immersion 
3 minutes at 60 .. . 
No growth. 
10 minutes after immersion ; . . 
‘ 5 minutes at 60 . . . 
Do. 
15 minutes after immersion 
10 minutes at 60 . . 
Do. 
Conclusion — The dysentery bacillus is somewhat more resistant to 
heat than the typhoid bacillus. It sometimes withstands heatmg at 
60° for five minutes. All are killed at 60° C. for ten minutes. How- 
ever, the great majority of these micro-organisms are killed by the 
time the milk reaches 60° C. 
