41 
found that when sterilized milk infected with fine suspensions of 
tubercle bacilli was exposed to 70° for ten minutes, 70° for thirty 
minutes, and 80° for thirty minutes, tuberculosis resulted in inocu- 
lated guinea pigs. 
Gal tier,® 1900, found that five to six minutes heating of milk to 
70° C., and even 85° C., was not sufficient to destroy the tubercle 
bacillus when that product is richly contaminated. He prepared an 
emulsion from the spleens and lungs of tuberculous rabbits, which was 
mixed up with the milk. He concludes from his studies that milk 
richly contaminated by the addition of tuberculous matter is not 
surely sterilized at 85° for six minutes. He recommends boiling as 
the only safe procedure to practice. 
Rabinowitsch,^ 1900, made the statement that recent investigations 
at the Institut fur Infektionskrankheiten in Berlin had shown that 
tubercle bacilli in milk are surely killed only by a temperature of 
100° C. Her results recalled attention to the fact that the tubercle 
bacillus, like all other organisms embedded in fat, is more resistant . 
to heat, and that this may account for the irregular results obtained 
by investigators. 
Russell and Hastings, 1900, made a valuable contribution to our 
knowledge of pasteurization, inasmuch as they applied the principles 
elucidated by Smith to work upon a practical scale. They made use 
of a Potts’ pasteurizer, which represents that type of machine which 
permits of heating milk for a specified time at a specified tempera- 
ture in a close chamber, thorough distribution of the heat being 
secured by the rotary movements of the machine. Bovine cultures 
of determined virulence were scraped from dog-serum slants rubbed 
up with a 0.6 per cent salt solution, sedimented to remove large 
clumps, and then the supernatant suspension was added in definite 
proportions to the milk. This infected milk, after control animals 
had been inoculated, was placed in small glass tubes closed with a 
cork and rubber guard, and these tubes were then heated in' a water 
bath up to the desired temperature and then dropped into the 
apparatus already raised to that point. During the exposure the 
temperature of the milk fluctuated no more than 1 degree and that 
only momentarily. The only temperature employed was 60° C. 
After a specified time the tubes were removed and the contents 
^ Galtier, V.: Le iait tuberculeux cesse-t-il d’etre dangereux apres un court chauf- 
fage a 70-75 degres? Compt. rend, des seances et mem. de la soc. de biol., vol. 2, 
2d ser., 1900, p. 120. 
& Rabinowitsch, Lydia: Dent. med. Woch., vol. 26, 1900, p. 491. 
c Russell, H. L., and Hastings, E. G.: Thermal death point of tubercle bacilli 
under commercial conditions. University of Wisconsin Agricultural Experiment 
Station, 17th Ann. Rep., 1900. 
