1890.] PUBLIC DOCUMENT — No. 4. 157 



the depth of cream in the gauge is a correct criterion of the 

 butter value of the milk. As I told you this morning, we 

 have a herd made up for experimental purposes, and we 

 have animals in tliat herd which, with the same amount of 

 butter fat in the milk, will show forty per cent diiference in 

 the amount of cream. That is, the body of cream which 

 from one animal would make one hundred pounds of butter, 

 from another animal Avould make one hundred and forty 

 pounds, there being a difference of almost one-half in the 

 butter derived from the cream. Now, that was not cream 

 under different conditions, but it was cream from the same 

 milking, set side by side in the same room, and under abso- 

 lutely the same conditions. They were both put into cold 

 water, and, although not submerged, yet the water covered 

 them so that the temperature of the air around them was 

 exactly the same. They were raised under exactly the same 

 conditions, yet we have found that wide variation when we 

 have tested them over and over again. And moreover, so 

 different is the character of the cream from different cows 

 and from different dairies, that taking the milk and putting 

 it into a centrifugal machine and whirling it for sixty thou- 

 sand revolutions will not compact the cream so that it will 

 be of equal value. There is no way of manipulating cream 

 by which you can make equal bulks of it produce the same 

 amount of l)utter. That point is perfectly clear. But when 

 3^ou come to the other point, whether churning cream will 

 afford a proper test of the butter value of a cow, there is 

 more chance for deception. I believe that the churn test, 

 setting the milk by itself, skimming the cream, and churning 

 it and weighing the butter, is not a correct way of estimating 

 the butter value of the milk of a cow. That may seem a 

 pretty bold statement, and if you are going to set the milk 

 of that cow by itself every time, I shall have to take it 

 back. If each time the milk of the cow is to be set by 

 itself and the cream churned by itself, then the butter is the 

 only accurate test of that cow ; but as soon as you take the 

 milk from that cow and put it with the milk from other 

 cows, you so change the way that it handles, you so change 

 the raising of the cream, and you so change the character 

 of the churning of that cream, that you cannot judge from 



