M. Galtier quoted as saying: "The result of my investigations 

 is that milk, abundantly inoculated with tubercle germs, is not 

 absolutely sterilized by heating for 6 minutes to 158, 176 

 and even 185, the milk from suspected animals should be 

 boiled for consumption by man or beast." 



Dr. Stohmann, in his book "Milch and Meiereiproducte," 

 says, page 402: "The killing of the bacteria will ~be promoted 

 through the sudden change of temperature" 



It seems to me there is a field open for careful experi- 

 ments because pasteurization will hardly become popular on 

 a large scale unless the continuous heaters and coolers may 

 be used under the approval of the scientists. 



But even if it is desired to keep the milk hot x for a cer- 

 tain time, it is, as T have before suggested, possible to use 

 a continuous heater and cooler by interposing three storage 

 tanks, each holding one-third of the hourly capacity of the 

 heater and cooler (if 20 minutes is the time) and thereby se- 

 curing the advantage of continuous apparatus and the sud- 

 den chilling of the milk. In Fig. 102, page 99, Mr. A. H. 

 Keid has solved the problem by interposing a sort of D. W. 

 heater as a storage tank. 



INTERMITTENT 'PASTEURIZATION. 



Dahl (Norway) proposed to heat the milk inclosed in ves- 

 sels to 158 for 3 hour, then cool to 104 for the same time, 

 then heat again and cool, in all four times. At last heat it 

 to 175 or 212 for half an hour and cool to 55 degrees. 



This is however neither sterilizing nor pasteurizing and 

 is simply a modification of the intermittent sterilization pro- 

 posed by Tyndall, and though very effective it is very com- 

 plicated and expensive. Large quantities of milk have never- 

 theless been shipped to London from Norway, preserved by 

 this "Dahl" method. 



The theory is that the comparatively low temperature 

 only kills the bacteria, and by cooling to 104 the germs are 

 given time to develop so as to be killed in the second heating. 



I have made a few experiments which lead me to believe 

 that if an increased safety and keeping quality is desired the 

 following process may be practical. It is simply a modifica- 

 tion of DahPs and is to heat to 155. Keep it there for half 

 an hour then cool to 100 and keep it between 90 and 100 for 



