Conclusion . — The cholera vibrio is similar to the diphtheria bacillus 
so far as its thermal death point is concerned. It is usually destro^^ed 
when the milk reaches 55° C. ; only once did it survive to 60° C. under 
the conditions of the experiments. 
BACILLUS DYSENTERIC. 
The only reference to the thermal death point of the B. dijsenterise 
I have been able to find is the work done under Kolle’s direction by 
Friedel, Kutscher, and Meinicke,® who found that the dysentery 
bacillus withstands a temperature of 60° for eight minutes, but is 
killed at 65° for two minutes. In these experiments it required five 
minutes to heat the milk from 15° C. to the temperature noted. 
I used eight different cultures of the dysentery bacillus, represent- 
ing both the Shiga and the Flexner types. ^ly results are given in 
the following tables: 
Experimext Xo. 41. 
B. Dijsenterise. ^ 
Three days’ growth in sterilized milk. Milk immersed in eonstant-lemperatiire 
water hath at 60 ° C. 
Milk culture. 
1 Teniper- ; 
! ature , 
(°C.). 
Loop of milk cul- 
ture in bullion. 
, X umber of 
1 colonies 
per loop in 
agar. 
“Duval;” reaction, 0. 126 per cent acid: 
At start 
I 
' 28 
Growth 
If minutes after immersion 
55 
do 
1,800 
2\ minutes after immersion 
‘ 58 
do 
28 
3j minutes after immersion 
60 : 
Xo growth 
0 
• 4| minutes after immersion 
(d 
do 
0 
“Sils; ” reaction, 0. 162 per cent acid: 
At start 
29 
Growth 
(&) 
1| minutes after immersion 
55 
do 
1.110 
24 minutes after immersion : 
58 
do.d 
56 
3 minutes after immersion 
60 
Xo growth 
0 
4 minutes after immersion 
do 
0 
‘ ‘ Kruse; ’ ’ reaction, 0. 187 per cent acid : 
At start .... 
28 
Growth 
(&) 
126 
1| minutes after immersion . ... 
55 - 
• do 
2J minutes after immersion . . 
do d . 
0 
3| minutes after immersion . 
58 1 
60 
Xo growth.. . . 
0 
4§ minutes after immersion 
(0 
do 
0 
“Mt. Desert; ’’ reaction, 0. 198 per cent acid: 
At start 
^ 28 
Growth 
(f>) 
57 
1 ^ minutes after immersion 
55 
do 
21 minutes after immersion 
58 
Xo growth 
14 
. 4j minutes after immersion 
60 
do 
0 
5x minutes after immersion 
(c) 
do 
0 
‘ ‘ Salant; ’ ’ reaction, 0. 189 per cent acid : 
At start. 
29 
Growth 
(&) 
(<>) 
154 
I 7 minutes after immersion. . . . . . . . 
55 
do 
2i minutes after immersion 
58 
do 
3S minutes after immersion . . 
60 
X^o growth 
0 
4§ minutes after immersion . . 
(^) 
do 
0 
a Friedel, Kutscher, and Meinicke: Die' Widerstandsfahigkeit der Erreger der wichtigsten Darm- 
krankheitengegen Erwarmen auf verschiedene Temperaturen in Milch. Klin. Jahrb.,vol. 3, 1904-5, p. 34. 
& Innumerable. c One minute at 60°. d Delayed. 
