126 ELEMENTARY AGRICULTURE 



hours, and compare the thickness of the cream layers. 

 Set aside for a few hours and compare again. \Yhat 

 difference do you observe? 



6. Into an unwashed bottle in which milk has been 

 allowed to sour place a sample of fresh, sweet milk. 

 Into another bottle that has been carefully cleaned 

 and scalded place another sample from the same sup- 

 ply. Set the samples side by side in a warm room and 

 smell and taste them at intervals of from four to six 

 hours. Record definitely the differences in preserva- 

 tion of the two samples. 



7. Take two samples from the same supply of 

 fresh, sweet milk, and place them in dishes that have 

 been carefully cleaned and scalded. Set one dish over 

 night in the barn, or in some other place where the 

 air is filled with bad odors. Set the other sample in 

 the open air or in a well ventilated place where there 

 can be no bad odors. Smell and taste of both next 

 morning. Has the bad odor affected the taste or odor 

 of the milk? From this experiment what do you 

 infer regarding the effects of bad air upon milk to be 

 used in making butter, or cheese, or for any other 

 purpose ? 



Free Bulletins, TJ. S. Dept. of Agriculture. 

 Farmers' Bulletins. 



No. 29. Souring of Milk and Other Changes in Milk 

 Products. 



No. 42. Facts about Milk. 



No. 55. The Dairy Herd : Its Formation and Management. 

 No. 57. Butter Making on the Farm. 



