44 
thermostat — i. e., under conditions where a pellicle would not be 
formed. The work is interesting especially because a liter of milk 
was used in the experiments. It is to be regretted that they did not 
experiment with lower temperatures. 
Barthel and Stenstrom,^^ 1901, report some preliminary work 
which must be interpreted as showing the influence of coagula in 
protecting the tubercle bacilli from the action of heat. This clot 
formation was probably due to the abnormal reaction of the patho- 
logical fluid from tuberculous udders employed. Animals injected 
with this material became tuberculous after it had been heated to 
75° for fifteen minutes and 80° for ten minutes. Temperatures and 
exposures sufficient to kill the tubercle bacilli under the conditions 
of the experiments were not employed. In tliis connection the sub- 
sequent work of these authors should be consulted (vide infra). 
Bang,^ 1902, reported a large number of experiments which give 
results at variance with those of this author’s former investigations. 
To avoid the formation of the surface pellicle and foam, in some of 
his work he exposed the milk in closed metallic boxes containing a 
thermometer immersed in a water bath and kept constantly in 
motion during the exposure to insure an equal distribution of the 
heat. As in former work, he used rabbits to test the virulence of 
exposed material by the intraperitoneal method. He experimented 
with pure cultures of the bacillus, noting whether growth was delayed 
or inhibited by exposure to heat, and further determined the effect 
of feeding the heated milk to rabbits and swine. The essential fea- 
tures of his results (under conditions which prevent the formation 
of scum) are as follows: 
Temperature and exposure. 
Result. 
60°, 15 minutes 
Prevented tuberculosis in 2 animals, but 2 others became 
slightly tuberculous. 
Effectually prevented tuberculosis. 
Do. 
65°, 1 to 15 minutes' 
70°, 75°, 80°, and 85°, momentarily 
Tuberculous milk from diseased udders was used in some of these 
experiments. 
Rabbits receiving one 30 c. c. feeding of milk exposed for two 
minutes to 60°, 65°, 70°, 75°, 80°, and 85° remained free from tubercle, 
although controls fed with raw milk became tuberculous. 
Swine fed with 150 c. c. each of tuberculous milk heated for half a 
minute at 60° became tuberculous, while those receiving milk heated 
to 70°, 75°, and 80° for half a minute remained sound. 
« Barthel, Chr., and Stenstrom, O.; Beitrag zur Frage des Einflusses hoher Tem- 
peraturen auf Tuberkelbacillen. Cent. f. Bakt., vol. 30, 1901, p. 429. 
6 Bang: Ueber die Abtddtung der Tuberkelbacillen bei Warme. Zeit. f. Tiermed.^ 
vol. 6, 1902, p. 81. 
