43 
tubes to certain temperatures by dropping them into boiling water. 
The infected tubes were therefore placed in boiling water for the 
time necessary to heat to the desired temperature and then placed 
in a water bath maintained at this temperature. After the lapse of 
the desired time they were cooled rapidly and injected into guinea 
pigs intraperitoneally. The results are shown in the table, + and — 
indicating that the animals became tuberculous or not. The results 
were controlled by examination after the death or killing of the 
animals. 
Temperature and time. 
Result. 
Temperature and time. 
i 
Result. 
65° 15 minutes 
1 
80°, 3 minutes 
ri8° l.'imiiintps 
85°, 5 seconds 
70°, 7 minutes 
85°, 5 minutes 
72°, 7 minutes 
89°, 30 seconds 
75°, 3 minutes . 
90°, 5 seconds 
75°, 5 minutes . . . 
(a) 
+ 
95°, 5 seconds 
80°, 5 seconds 
a Pseudo-tubercle, Pfeiffer. 
As the most practical temperature and exposure, Herr recommends 
85° for two minutes for cream from which butter is to be made. This 
is obtaiued in the “continuous” form of apparatus. 
Hesse,® 1901, corroborates Smith’s findings. Sterilized milk inoc- 
ulated with a culture of human tubercle bacilli several weeks old was 
sealed off in small tubes and these dropped into a Pfund’s sterilizer 
previously heated. After twenty minutes exposure they were taken 
out and cooled and the contents injected into guinea pigs. The ani- 
mals were killed after fifty-five days. Controls receiving unheated 
milk had high-grade generalized tuberculosis. Pigs receiving milk 
heated at^ 57° for twenty minutes had less severe lesions; those 
receiving milk heated at 58° for twenty minutes had still severe 
lesions, and one receiving milk heated at 60° for twenty minutes was 
entirely sound, the other having a small translucent nodule in the 
‘diaphragm, in which no tubercle bacilli were found. 
The experiments corroborate Smith’s findings. The gradation of 
severity of lesions inveAely with the increased temperature is inter- 
esting. 
Levy and Bruns, ^ 1901, showed that a temperature varying be- 
tween 65° and 70° C. and operating for fifteen to twenty-five minutes 
effectually killed bovine and human tubercle bacilli in milk, when 
1 liter of the artificially infected milk was exposed in a d’Arsonval 
Hesse; Ueber die Abtodtung der Tuberkelbacillen in 60° C. warmer Milch. Zeit. 
Tiermed., 1901, voL 5, p. 5-6. 
Levy, E., and Bruns, Hugo: Ueber die Abtodtung der Tuberkelbacillen in der 
Milch durch Einwirkung von Temperaturen unter 100°. Hyg. Runds., vol. 11, 
1901, p. 669. 
