56 
Expeeiment No. 11. 
B. typhosus. 
Culture, “Hopkins;” forty-eight hours’ growth in whole milk that had been steril- 
ized by the fractional process three days. Reaction, 0.252 per cent acid. 
The milk at 21° C. immersed in constant-temperature water bath at 60° C. 
Milk culture. 
Temperature (° C.). 
1 c. c. milk culture 
in bouillon. 
At start 
21 
Growth. 
2 minutes after immersion. 
55 
‘ Do. 
2J minutes after immersion. 
57 
Do. 
3 minutes after immersion 
59 ' 
1 Do. 
4J minutes after immersion 
60 
Do. 
minutes after immersion 
1 minute at 60 
Xo growth. 
Do. 
6^ minutes after immersion 
2 minutes at 60 
7J minutes after immersion 
3 minutes at 60 
Do. 
9j minutes after immersion 
5 minutes at 60 
Do. 
14j minutes after immersion 
10 minutes at 60 
Do. 
Experiment No. 12. 
B. typhosus. 
Culture, “P. I.;” forty-eight hours’ growth in whole milk that had been sterilized 
by the fractional process three days. Reaction, 0.288 per cent acid. 
The milk at 21° C. immersed in constant-temperature water bath at 60° C. 
Milk culture. 
Temperature (° C.) 
1 c. c. milk culture 
in bouillon. 
At start . . 
21 
Growth. 
Do. 
Do. 
Do. 
Do. 
Xo growth. 
Do. 
Do. 
Do. 
Do. 
minutes after immersion . . 
55 
2 minutes after immersion 
57 
2i minutes after immersion. 
59 
3| minutes after immersiom 
60 
4§ minutes after immersion 
1 minute at 60 
5| minutes after immersion 
2 minutes at 60 
6| minutes after immersion. ... 
3 minutes at 60 
8§ minutes after immersiom 
5 minutes at 60 
1.3S minutes after immersion 
10 minutes at 60 
Conclusion . — The evidence is plain that milk heated to 60° C. 
and maintained at that point for two minutes will kill the typhoid 
bacillus. The great majority of these organisms are killed by the 
time the temperature reaches 50° C. and few survive to 60° C. 
BACILLUS DIPHTHERI.E. 
REVIEW OF THE WORK OF OTHERS. 
Welch and Abbott,® 1891, tested the thermal death point of the 
diphtheria bacillus upon bouillon cultures and suspensions, in ster- 
lized salt solution, in capillary^ glass tubes, and found that the bacillus 
« Welch and Abbott: The etiology of diphtheria. Johns Hopkins Hospital Bull., 
vol. 2, 1892. 
