37 
Forster,® 1892, sealed off small glass tubes containing for the most 
part the milklike material squeezed from the cut surface of tuber- 
cular udders and placed these in a water bath kept at the desired 
temperature for various periods. They were then cooled quickly 
and injected intraperitoneally . into guinea pigs. The presence or 
absence of living tubercle bacilli was determined by autopsy, by 
the lesions, or by carrying the suspect material over into other ani- 
mals. The bacilli appeared not to be killed by three hours exposure 
to 55°, forty-five minutes exposure to 60°, or momentary exposure 
to 80°, but were killed by six hours exposure to 55° (sputum), one 
hour exposure to 60° and 80°, momentary exposure to 95°. These 
figures indicate a high degree of resistance. 
It is difficult to explain the high figures obtained by Forster, 
especially in the light of the work of Smith, Russell and Hastings 
and my own. 
The next year the same author,^ reviewing the situation, empha- 
sizes that pasteurizing apparatus is of two kinds; (1) in which the 
milk passes over heated surfaces and is momentarily raised to a 
given temperature, and (2) in which the milk is heated in kettles, 
bottles, etc., and may be kept for a certain time at the desired tem- 
perature. He says that the latter are the only ones applicable to 
milk containing tubercle bacilli, because momentary heating to tem- 
peratures insufficient to change the* taste of the milk does not kill 
tubercle bacilli. 
De Man,^^ 1893, working under Forster, obtained results long cur- 
rent in text-books and which have been accepted as the standards 
for practical work in many regulations for dairy methods. The fol- 
lowing brief summary of early work on the subject culled by him 
from Galtier (1879) shows the discrepancies and inadequacies of this 
period — faults, however, which continue to appear in recent work: 
Author. 
Temperature. 
Time. 
Result. 
Chaveau and Arloing 
Touissaint 
Gerlach 
Martin 
Klebs 
70°, 100° 
73°, 76°, 80°.. . 
100° 
80°, 100° 
30 minutes. . 
(?) 
30 minutes.. 
1 (?) 
! 
No certainty of kiUing tubercle baciUi. 
Virulence remains. 
Virulence remains, but weakened. 
Virus vdthstands this heat. 
Boiled milk may cause tuberculosis. 
Boiled tubercular sputum innocuous. ^ 
Paper impregnated with tubercle bacilli 
loses \drulence by dipping in boiling 
water. 
1 
Frerichs, Parrot, and Martin. . 
Vallin 
aForster, J.: Ueber die Einwirkung hoher Temperaturen auf Tuber kelbacillen. Hyg. Runds., 
vol. 2, 1892, p. 869. 
& Forster, J.: Ueber die Einwirkung hoher Temperaturen auf Tuberkelbacillen. Hyg. Runds., 
vol. 3, 1893, p. 669. 
cDe Man, C.: Uber die Einwirkung von hoher Temperaturen auf Tuberkelbacillen. Arch. f. Hyg., 
vol. 18, 1893, p. 133. 
