290 REFERENCES 



as a center of educational activities. A tendency may arise, however, 

 to expect certain work to be done at home which can be done better in 

 school. It is better, for some pupil, or the teacher, to bring to 

 school specimens of the alfalfa plants for study as a class exercise than 

 to have the pupils study the plant at home. The pupils are all together 

 in the class, and the teacher is present to instruct and to inspire them. 



2. Pupils should be taught to draw, measure, and describe accurately 

 such plant material. It is better to get a little definite first-hand 

 knowledge of a few things than a smattering knowledge of many 

 things obtained through the eyes of other people. 



3. Take the class into a neighboring field in which leguminous 

 plants are growing. Dig up a specimen of alfalfa, clover, or beans. 

 Show the tubercles or nodules on the roots and explain their function. 



4. Sprout about a dozen alfalfa seeds in a Pasteur dish or by some 

 other method. When the roots are an inch long insert them into the 

 meshes of a piece of fly-netting and allow them to hang in the water 

 of a wide mouth bottle. Add a few drops of phenolphthalein to the 

 water and enough weak limewater to give the solution in the bottle a 

 marked reddish tint. Examine in a few days. Does the color of the 

 water fade out? Explain. 



Sprouting seedlings of any kind thrown into a weak solution of lime- 

 water, colored red with phenolphthalein, will decolorize the water in a 

 short time. This is a most striking experiment to prove that roots in 

 activity throw off acids. 



REFERENCES 



Farm Grasses of the United States. Spillman. 

 Forage and Fiber Crops in America. T. F. Hunt. 

 Farmers' Bulletins. Washington, I). C. 

 66. Meadows and Pastures. 

 72. Cattle and Ranges of the Southwest. 



237. Lime and Clover. 



278. Leguminous Crops for Green Manuring. 



318. Cow Peas. 



339. Alfalfa. 



372. Soy Beans. 



458. The Best Two Sweet Sorghums for Forage. 



578. The Making and Feeding of Silage. 



485. Sweet Clover. 



508. Market Hay. 



