438 EXPERIMENT STATION RECORD. 



which are stoppered with cotton and then placed in the cylinders. 

 Sufficient water is poured into each cylinder to surround the body of 

 the bottle, and the receptacle is thenijlaced in the pail, which is removed 

 from the stove, the cover quickly replaced, and the whole allowed to 

 stand for three-quarters of an hour. A support for the receptacle is at 

 such a height that the lower inch of the cylinders is immersed in the 

 water. "During the first 15 minutes the temperature of the milk rises 

 to . . . about its maximum, or above G5°, the point desired for pasteur- 

 izing, and remains there the remaining 30 minutes. During the last 15 

 minutes it falls about 1°." At the end of the 45 minutes the cover is 

 removed, the receptacle is lifted so that it rests on a higher support, 

 raising the tops of the cylinders above the top of the pail, and cold 

 water run into the pail and allowed to overflow. In about 15 minutes 

 the milk in the bottle is said to be about the temperature of the cold 

 water and the bottles are removed and placed in a refrigerator. 



A chart is given showing the changes in temperature of the milk 

 during the operation, and the author calls attention to the following 

 points : 



"(1) The apparent lack of precision in the action of the apparatus, due to the 

 unknown temperature of the milk introduced, is to a considerable extent corrected. 

 The amount and temi)erature of the boiling water used for heating is definite; the 

 amount of cold milk to belieated is definite, but the temperature of tlie milk is such 

 as may be covered by the word cold or by refrigerator temperature. The chart 

 shows that the apparatus will correct a considerable variation of the temperature of 

 the milk used l)y the ability of the boiling water to carry cold milk through a 

 greater number of degrees of temperature than warmer milk; on this account 

 whether the milk is introduced at a temperature of 10° C. (50" F.) or 20° C. (68" F.), 

 the resultant temperature varies only 2° C. 



" (2) The very rapid rise in the temperature of the milk introduced. It rises about 

 35 or 40" in the first 5 minutes, about 10" in the second 5 minutes, and about 5° in 

 the third 5 minutes. 



"(3) The even temperature preserved after the rise; a variation of not more than 

 a degree during the last 25 minutes. 



"(4) The rapid fall of the temperature in a cold-water bath; a fall of about 35° 

 in the first 5 minutes. This cooling in a cold-water bath takes places 8 times as fast 

 as in a refrigerator." 



Facts about milk, R. A. Pearson ( (J. 8. Dept. Agr., Farmers'' Bui. 

 42, pp. 28, figs. S). — This is a popular presentation of certain facts in 

 regard to the extent of the dairy industry of the country; the physical 

 and chemical character of milk; the changes in milk; difiBculties of 

 obtaining pure milk ; adulteration; preservatives; care of milk, includ- 

 ing description of the method for pasteurization previously described 

 in a circular of the Department; various methods for detecting adul- 

 teration of milk ; careof milk on farms; transportation of milk ; audits 

 delivery in cities, together with certain suggestions for improvement. 



The author advocates selling milk on the basis of its quality, the 

 price being in proportion to the fat content. 



"The grades of milk should be numbered with the whole numbers nearest to the 

 percentage of fat content. Thus a separator skim milk with but a trace of fat would 



