No. 4.] SANITARY MILK. 103 



and could cool it very quickly in running it over that. We 

 found last summer, when we were attempting to conduct ex- 

 periments in the cost of making milk under certain condi- 

 tions, that after twenty-four hours the milk contained less 

 bacteria per c. c. when we took samples from the pails warm 

 than from the receptacle cool. We put that aerator in a glass 

 case, where the air was not in circulation and where there 

 was no opportunity for dust to get in, and we found we had 

 just about the same per cent of Ijacteria in the milk after it 

 was aerated as before ; they were practically the same. I 

 thoroughly believe that you will get good results if milk l)e 

 cooled down in Inilk very quickly in fifteen or twenty min- 

 utes from the time that it was drawn from the cow. 



Professor Cooley. That is not aeration, then, — it is 

 merely cooling ; it is aeration without air. 



Mr. Dawley. It is cooling, — simply thorough and quick 

 cooling. 



Professor Cooley. You spoke of the dipping of milk from 

 cans, as retailed in New York. The Massachusetts custom 

 is to pour into cans of a smaller size ; but I know, in this 

 city at least and a few in some other places, of retailers mak- 

 ing a difference of 1 cent a quart between the milk in glass 

 and that which is retailed in bulk, holding that it costs them 

 about that much more to handle it in glass than it would in 

 bulk. In my own experience I find that it costs somewhere 

 between -J^ and -^ of a cent a quart to put milk into glass 

 and handle it that way ; that is, that covers the cost of break- 

 age, and things of that kind. To offset that, there is quite 

 a l)ill for spilling and over-measure in the retailing in bulk ; 

 that I think will fully equal the yL or ■^, if milk is 6 or 7 

 cents a quart. Personally, I should prefer to have all milk 

 in glass. There are other packages that are coming into use 

 that will l>e non-returnal)le, which may be still better in some 

 ways, although in other ways not. 



Mr. Dawley. I think Professor Cooley is very fortunate 

 in handling his milk and putting it up in glass so economi- 

 cally, and I think you might take his figures as the minimum, 

 rather than the average cost. It simply shows that he has 

 taken great pains to perfect his methods. 



