How tlw Plant Grows. 11 



2.2 per cent, crude fiber, while clover hay yields nearly 25 

 per cent. 



21. Ether extract or fat. A sample of the fodder, dried so as 

 to be free from water, is treated with ether, which has the power 

 of dissolving fat, wax, resins and similar substances. The matter 

 extracted by ether is quite commonly called "fat" in works on 

 plant analysis. In this book it is always spoken of as "ether 

 extract." In seeds nearly all the ether extract is fat or oil, and 

 has a corresponding feeding value. In plant leaves and stems 

 much of the ether extract is wax, chlorophyll and other substances 

 of lower feeding value than fat. Mangels are shown by the table 

 to yield only .2 of a pound of ether extract per 100, while corn 

 reaches 5 per cent. 



22. Nitrogen-free extract. Mtrogen-free extract signifies what 

 is left of the organic matter of the plant after deducting the pre- 

 ceding groups of compounds. It contains starch, sugar, pento- 

 sans, gums, organic acid and other bodies. The nitrogen-free 

 extract and the crude fiber together constitute the carbohydrates 

 of the plant physiologist. Nitrogen-free extract is determined 

 by difference. The total dry matter in the fodder, minus the ash, 

 ether extract and crude fiber, equals the percentage of nitrogen- 

 free extract present. The great difference between plants and 

 seeds as to woody matter is shown in the table. Over 70 per 

 cent, of the substance of corn and only about 38 per cent, of 

 clover hay is nitrogen-free extract. 



