42 
injected intraperitoneally into guinea pigs. The results are clearly 
shown in the following tables : 
Time exposed. 
Result in each series. 
I. 
II. 
III. 
IV. 
V. 
60°, 45 minutes 
60°, 30 minutes 
1 
1 
60°, 20 minutes 
60°, 15 minutes 
I 
60°, 10 minutes 
+ + 
+ 
' + + 
+ 
60°, 5 minutes 
(^)ntrol 
+ 
i ^ 
+ 
— = No tuberculosis. 
+ = Tuberculosis. 
Two pigs in each experiment. 
A series was then run which shows the difference in effect of heating 
in open vessels and in sealed or closed tubes, the latter being placed 
in Potts’ macliine. 
Series VI . 
, Series VII. 
Time exposed. 
Potts’ 
sealed 
tube. 
Open 
bottle. 
: Potts’ 
i sealed 
j tube. 
Open 
1 bottle. 
60°, 15 minutes 
+ + 
60°, 10 minutes 
'+ + 
+ + 
60°, 5 minutes 
+ + 
+ + 
+ + 
Control.. . . 
+ 
+ 
— = No tuberculosis. 
+ = Tuberculosis. 
Two pigs in each experiment. 
In their experiments, milk heated at 60 degrees began to show 
visible signs of pellicle after about twenty minutes, but the authors 
think that flocculent patches exist before tliis. For practical work 
they advise pasteurization at 60 degrees for twenty minutes m closed 
apparatus. 
Herr,® 1901, worked vuth cream only. Here the problem is 
different from that of milk pasteurization. It is not necessary to 
avoid those temperatures which change the taste of the product, 
wliich is used for making butter, and hence a liigher temperature and 
very brief exposure may be employed, permitting the use of the so- 
called continuous pasteurizers which operate vuth a great economy 
of time and fuel. In Herr’s experiments cream was shaken up vuth 
tuberculous sputum, the mixture sealed off in tubes of 4 c. c. capacity, 
leaving as little air as possible in the tubes. He had previously 
determined how long it would take to heat the contents of such 
oHerr: Das Pasteurisiren des Raliines als'Schutz gegen die Verbreitung der Tuber- 
kelbacillen durch Butter. Zeit. f. Hyg., vol. 38, 1901, p. 182. 
