154 MODERN DAIRY PRACTICE. 



in the samples of milk investigated. Hueppe has later pre- 

 scribed that the intermittent sterilization of milk takes 

 place best by exposing it to live steam at 212 F. during 

 the first day for an hour, and during each of the follow- 

 ing two or three days for twenty to thirty minutes. As 

 already stated, a separation of the albumen of milk takes 

 place at this temperature, its behavior toward rennet is 

 changed, and an almost imperceptible change in some of 

 the milk-sugar takes place. 



The intermittent sterilization applied in laboratories 

 has also been introduced in practice for the preservation 

 of milk by the Norwegian Chr. Gerhard Dahl of Dram- 

 men, who succeeded so well in this that at the last Paris 

 Exposition he could show milk several years' old prepared at 

 his factory. This milk is said to have been very palatable, al- 

 though it possessed a distinctly cooked taste, which, however, 

 according to a statement made by a visitor at the Exposition, 

 was no more pronounced than that of ordinary boiled milk. 



Dahl describes his method in the following manner in 

 the letters-patent granted in Germany November 14, 1886 

 (quoted from Molkerei-Zeitung] : 



The method of condensing the milk consists in (1) cool- 

 ing the newly-drawn milk to 50-64 F. (10-15 C.); (2) 

 filling the milk into cans; (3) air-tight stoppering; (4) heat- 

 ing of the cans to about 158 F. (70 C.) for about one and 

 three quarters of an hour; (5) cooling to 104 F. (40 C.) for 

 one and three quarter hours, and then (6) rapid heating of the 

 milk to 158 F. (70 C.); (7) repetition of these three pro- 

 cesses heating, cooling, heating with about one-half-hour 

 intervals; (8) a final heating for one half -hour to 176-212 

 F. (80-100 C.); and finally (9) cooling to 59 F. (15 C.). 



Good results can doubtless, as a rule, be obtained by 

 this or a similar method of procedure. Difficulties of all 



