EXPERIMENT bTATION BULLETINS. 213 



The can is placed in a galvanized tank lined on the outside with inch 

 matched boards and over which is a wooden cover with a hole in the 

 center for the protrusion of a part of the can cover, and a small hole in the 

 corner for the thermometer. 



The bottles used had a neck so fitted that a hot paraffined paste-board 

 circular cover could be pushed down tightly and covered farther with 

 paraffin. 



The Process. — The apparatus and bottles were steamed for thirty min- 

 utes before using. After the milk had been placed in the can and the can 

 in the tank, the parts were adjusted for conducting the work of heating. 

 The water in the tank was kept equal in heighth with the milk in the can 

 and the steam turned on from time to time as required to keep the water 

 at the proper temperature, which was not allowed to exceed 70° C. [158° 

 F.]. During the heating the milk was stirred constantly. As soon as 68° 

 C. [155° F.] was reached by the milk, the stirring was stopped and the 

 water in the tank was held at 68° C. [155° F.] for twenty minutes. At 

 the expiration of twenty minutes, the can was removed from the heat- 

 ing tank and placed into a cooling tank containing a freezing mixture 

 and the milk was constantly stirred while cooling. When the tempera- 

 ture had fallen to 10° C. [50° F.] or below, the can was removed and 

 the milk drawn off into bottles. In drawing off the milk, the cap was 

 first removed from the faucet and the mouth-piece substituted, care 

 being used in handling the mouth-piece where the milk does not touch 

 it. A little of the milk was drawn off at first before drawing into the 

 bottles to rinse the mouth-piece, although sterilized. When the bottle 

 was nearly filled the milk was turned off and the hot paraffined cap imme- 

 diately placed on the mouth of the bottles. In handling the bottles, 

 they were taken from the sterilizer when wanted, in an inverted posi- 

 tion only and the mouth was not turned uppermost till it was adjusted 

 to the mouth-piece and underneath the three inch flange. 



THE STUDY OF SAMPLES. 



After Pasteurization two bottles were brought to the laboratory, and 

 also, with them, two bottles of the same lot of milk, put up with sealed 

 mouths just as the other but un-Pasteurized. These latter were regarded 

 as controls. In the first half of the samples the data is very limited, 

 but in the second half, care was exercised in several details which may 

 not have any direct value in the work, yet these very details will help 

 to check the work; consequently a history of each sample which may 

 be referred to when desired, will be appended. 



But before considering the samples by themselves, we wish to say 

 that one sample bottle of the Pasteurized milk of each lot was opened 

 and several plates were made from it; also it was tested for acidity. 

 One of the un-Pasteurized sample bottles was also opened and tested 

 for acidity. 



The other sample bottle of each lot of Pasteurized milk and the other 

 of each lot of un-Pasteurized milk were placed away at room-temperature 

 and when changed were tested for acidity, odor and other qualities, 

 as shall be noted in the historv of each. 



