SPECIAL POINTS. 55 



weighing the cream on scales, but this is hardly 

 necessary in ordinary work on the farm or at the 

 creamery. 



To test cheese, it is necessary to weigh from four to 

 six grams of the sample and place carefully in a 

 Babcock -bottle, preferably a cream bottle. Then add 

 1 2 to 15 c.c. of hot water, and shake thoroughly until 

 the cheese is nearly all dissolved. Then add the 

 sulphuric acid, and proceed as in testing milk. If six 

 grams be taken, the percentage of fat is got by mul- 

 tiplying the reading by three. If four or five grams 

 are taken the percentage of fat equals 



e.g., four grams of cheese give a reading of 8.8. The 

 per cent, fat = 8 -^ = 39.6. 



SPECIAL POINTS. 



Accuracy is necessary in all parts of the work, else 

 it is without value. 



Burnt readings are usually caused by too strong 

 acid, by allowing the acid to fall through the milk, by 

 allowing the sample to stand too long after adding 

 the acid, or by having the milk or acid at too high a 

 temperature 60 to 70 degrees is favorable. 



Curdy matter in the fat is usually caused by the 

 acid being too weak, the milk, or acid too cold, or 

 through improper mixing of the milk and acid. 



Churned samples should be heated to about no 

 degrees F., then be mixed and sampled quickly while 

 the liquid fat is mixed with the serum. 



Partly frozen milk should not be sampled, if it can 

 be avoided, until the frozen part is melted and mixed 

 with the liquid. 



