BIOLOGY AND AGRICULTURE 493 



Horses for trotting, running, draught, or mere appearance, are 

 bred and selected and their pedigrees so carefully recorded that 

 many a trotter can trace his ancestry much farther back than 

 most human aristocrats. The advantage lies with the horse in 

 another way, since his ancestors were valued because they could 

 do something well, and not merely because of the accident of birth. 



Bacteria on the Farm. Care of milk on the farm has been al- 

 ready mentioned, but in cream, butter, and cheese as well, the 

 farmer is using some bacteria and opposing others. The char- 

 acteristic flavors and odors of butter and cheese are due to use- 

 ful bacterial action, 'while the spoiling and decay of these products 

 is due to attack of others. 



Bacteria are working also in the preparation of ensilage and 

 the " curing " of meats and tobacco. In fact if you will look back 

 over your work you may be surprised at the extensive role of 

 bacteria as farm laborers. 



Here are some of their activities, good and bad: 



They aid in decay of organic matter for fertilizers. 



They cause decay of valuable foodstuffs. 



They help return nitrogen to the soil. 



They cause many plant and animal diseases. 



They aid in all dairy processes. 



They spread disease by way of milk and other foods. 



They help in producing ensilage. 



They aid in curing meats, flax, and tobacco. 



There is no branch of industry so important, and none so closely 

 associated with biology as the industry of agriculture. Most of 

 the material found in the chapters on economic biology both of 

 plants and animals, together with much under forestry and gen- 

 eral conservation methods, bears directly on this fundamental 

 occupation. 



COLLATERAL READING 



Agriculture for Beginners, Burkett, Stevens and Hill; The Fertility of 

 the Land, Roberts; Soil Fertility and Permanent Agriculture, Hopkins; 

 Principles of Agriculture, Bailey; Farmers for Forty Centuries, King; Fer- 

 tilizers, Voorhees; Practical Agriculture, Wilkinson; First Book of Farm- 

 ing, Goodrich; Cyclopedia of American Agriculture, Yols. II and III; 



