138 



THE CHEMISTRY OF THE FARM 



we find that the composition depends largely on the 

 stage of growth in which the plant is taken, and is also 

 greatly affected by the character of the manuring. It 

 may be generally stated that as a plant matures the 

 proportion of water, nitrogenous matter, and ash con- 

 stituents diminishes, while the proportion of carbo- 

 hydrates and fibre increases; at the same time the 

 amides become more or less converted into albuminoids. 

 The following table shows the percentage composition 

 of meadow grass cut at three different dates in the 

 same field. The first cutting will represent pasture 

 grass fed off in the green state by stock; the second 

 cutting is good ordinary hay; the third cutting is an 

 over-ripe hay, somewhat coarse and stemmy, but well 

 harvested. The composition given in every case is 

 that of the dry substance : — 



COMPOSITION OF MEADOW HAY HARVESTED AT 

 DIFFERENT DATES. 



The albuminoid nitrogen amounted in the first 

 cutting to 65*2 per cent., in the second cutting to 84*0 

 per cent., and in the third cutting to 92'5 per cent, of 

 the total nitrogen. 



Young grass is much richer in albuminoids, and 

 contains a smaller proportion of indigestible fibre than 



