ILLINOIS STATE DAIRYMEN S ASSOCIATION. I37 



can untilize three-fourths. Grass, like all vegetable matter, is 

 built up of cells, each surrounded with a coating of material 

 which, from its being so found, has been termed cellulose. 

 Within these cellulose walls are contained the sugar, starch, 

 and albumen of the plant. In a tree, as each year new cells are 

 formed the old ones lose their contents, dry up, and become 

 wood. The succulent cellulose of the living cells is entirely 

 different from this woody cellulose. The former a cow can 

 digest and utilize, the latter is no food; indeed when taken in 

 excess, woody cellulose is detrimental to cattle. This change 

 of digestible succulent cellulose into indigestible woody cellulose 

 (or fibre, as it is . often called) is one which takes place in the 

 conversion of grass into hay. Moreover, it takes place in every 

 forage and succulent crop as it approaches ripeness, and especi- 

 ally after it flowers; hence the necessity of cutting such crops 

 before they are over-ripe. The second change which takes 

 place in the conversion of grass into hay is due to fermentation 

 and oxidation. These processes burn up the constituents of the 

 grass, producing heat, and, if the partially-dried grass be stacked 

 before this combustion of the cell-contents is finished, the heat 

 may become so great as to produce flame. 



Thus we are now able to explain why the dry food, hay, is 

 so inferior to the succulent food, grass. So far as the loss of dry 

 matter is concerned, it might be made up by the use other dry 

 foods; 'but this has not been found satisfactury in practice, and, 

 to make up for the inferior nature of hay, it has been found 

 essential to employ some succulent food. The use of the root 

 crops, swedes and mangels, has thus become universal in winter 

 dairying; but it may not be generally realized that in order to 

 supply these crops one-fifth of the total cultivated land of Eng- 

 land, Scotland, and one-tenth that of Ireland, other than land laid 

 down to grass and clover, has to be devoted to their growth. 

 Thus, in England, 2,300,000 acres are annually cropped with 

 turnips, swedes, and mangles; in Scotland, about 500,000 acres; 

 and in Ireland, 350,000. So that over 3,000,000 acres are de- 

 voted to the growth of crops, and at least 45,000,000 tons of 



