306 Report oF THE CHEMIST OF THE 
In regard to the amount of the fat in butter, we have placed it at 
85 per cent., believing, from all published data, that this figure 
represents more nearly the composition of average butter as 
found in the market than does 80 per cent. of fat, the figure 
adopted for the World’s Fair test. 
The standards above given for loss of fat in butter-making and 
for per cent. of fat in butter we shall adhere to throughout this ~ 
investigation. The work done during the past four years all goes 
to show that the amount of fat in milk is the sole guide in regard 
to the amount of butter that can be made from milk, provided 
our conditions of creaming, churning and working are uniform, 
conditions which are now largely under our control. Those who 
still contend that only by the churn we can accurately determine 
the amount of butter production must have failed to follow the 
results of the last four years’ investigation in this country or else 
must have entirely failed to comprehend what those results 
mean. If one can not make agree the results of the churn and 
the results of calculation of butter yield from the amount of fat 
in milk, the fault lies every time with the manipulator and his 
methods of creaming, churning, etc. One great advantage in 
being able to calculate the butter yield from the amount of fat 
in milk depends upon the fact that we have in this a means of 
measuring the skill of the butter maker and his methods. We 
can thus tell whether the yield is as much as it should be, and in 
case of shortage, we can find the sources of loss. 
During the first period of lactation of most of our cows, we 
used the deep-setting process of creaming and made butter. 
These results have already been published (Tenth Annual Re- 
port, pp. 300-364), and also a comparison of these results with 
results secured by the method of calculation (Eleventh Annual 
Report, pp. 467-469). 
In connection with this study,of the comparison of different 
breeds of dairy cows we shall consider the following subjects: 
1. Per cent. of fat in milk. 
2. Amount of milk-fat produced. 
3. Amount of butter produced. 
4. Amount of butter made from 100 pounds of milk. 
5. Amount of milk required to make one pound of butter. 
