Rural School Leaflet. 727 



what part of the fowl the feather was taken. Any teacher will see that 

 this will at once interest the children in finding feathers, and in noting 

 poultry more closely as they see them in the barnyard. Patient inquiry 

 is ever fundamental to scientific work. 



THE LESSONS ON POULTRY 



Professor Rice has been preparing a series of lessons on poultry for 

 the Cornell Rural School Leaflet. His expert knowledge on the 

 subject will be of benefit to every child in the rural districts in New York 

 State. The lessons are planned so that children may have an educational 

 outlook to the subject. 



One who is successful in raising poultry must know poultry, not 

 merely a few facts on the practical side of poultry raising. There are 

 problems that come to the farmer in this line of work that he must solve 

 for himself. He can do this best if he has some scientific basis for the 

 work. 



One or two teachers have asked us to tell the children how to make 

 money in poultry raising, rather than to give them instruction along 

 scientific lines. This is a mistaken idea. If the observation of a child is 

 trained so that he can readily see, and his reasoning powers are suffi- 

 ciently developed to find out something about what he sees, he will be 

 prepared to carry out practical problems. 



In his articles this year Professor Rice is endeavoring to give children 

 a knowledge of poultry. If teachers will see that these lessons are prop- 

 erly given with actual material, the children will have a fundamental 

 preparation for poultry raising. Let knowledge come first, and practical 

 suggestions can then be given with some hope of results. 



Lesson XXI 

 WHY MILK SOURS 

 By W. A. Stocking, Jr. 



^ , _ r--' -■ Object. — To call the pupil's attention to some 



4;,. , ^_ of the invisible forces constantly working about 

 -- ■< ^ ~^^ '^^' ^^'^ ^^ explain the cause of one of the things 

 *^- -' with which we are all familiar — why milk sours. 



Material. — A little milk, a few glass jars and 



a thermometer. 



Everyone knows that if milk is allowed to 

 stand in a warm room for any length of time, it 

 becomes sour and finally curdles. Not everyone, however, knows why 

 these changes take place in the milk. 



Milk becomes sour and curdles because it contains bacteria, which 

 change the milk sugar into lactic acid. At first, milk usually contains 



