26 AGRICULTURE OF MAIXE. 



mal physiology and bacteriology have also contributed to the 

 science of feeding, as also have unclassified scientific studies of 

 peculiar interest to this particular branch. Wolff and Lehman 

 and Armsby and others have marked the last few decades as of 

 exceeding importance in scientific studies of animal nutrition. 



WHY DISCUSS SCIENTIFIC FEEDING WITH FARMERS. 



A great deal is being published at the present time in relation 

 to feeding, by experiment stations, departments of agriculture, 

 and the agricultural press that would have been so poorly under- 

 stood a decade or two ago by farmers as to be of no interest or 

 value to them. Times are rapidl\- changing. Farmers now 

 discuss familiarly feeding terms, e. g., protein, carbohydrates, 

 standards, nutritive ratio, digestibility, etc., that would have then 

 been utterly unintelligible. It is to still further increase this 

 understanding of scientific publications that we pause to discuss 

 the scientific side of this great industry. To enable the farmer 

 to comprehend the publications pertaining to his art is an impor- 

 tant work, and a few minutes devoted to the discussion of some 

 of the more abstract principles of feeding will be better appre- 

 ciated when we consider the mine of scientific information 

 thereby made more available. 



ANALOGY BETWEEN PLANTS AND ANIMALS. " , 



There is a close analogy between plant feeding and animal 

 feeding. As we have become familiar with the use of three 

 essential elements of fertility and plant food in soils, viz.. nitro- 

 gen, potash and phosphoric acid, we may consider that the 

 animal organism also requires three kinds of feeding matter in 

 order to become perfectly developed and profitable. While 

 plants are able to feed upon the simple compounds existing in 

 the soil and the air. animals need more complex food supplies 

 as are produced by the processes of vegetation. The three 

 classes of nutrients recognized in feeding animals are protein, 

 carbohydrates and fat. \\'ater is of equal importance to both 

 plant and animal life, but while with the plant we pay particular 

 attention to the important mineral nutrients and practically 

 ignore the carbon which is supplied by the air, in feeding 

 animals we relegate the mineral constituents to the background 



