64 ORIGIN AND 



sists almost entirely of nitrogen. Those anin als 

 therefore which exist on the flesh of other ani- 

 mals consume a much larger quantity of this 

 nitrogea, than those which exist on vegetables 

 alone, and the system of the former not re- 

 quiring all the nitrogen for its support, the excess 

 must be carried off by the natural vents, and 

 accordingly it is found that in proportion as the 

 animal is either carnivorous or otherwise, so is 

 the urine rich in ammonia; and farther it is re- 

 marked that amongst herbiferous animals, in 

 proportion as the food is rich in nitrogen, (and it 

 has been shown that wheat and all grains con- 

 tain that principle) so will be the contents of 

 the urine. 



Acting on this principle then, it is found that 

 100 parts of wheat grown on a field manured 

 with cow-dung, (manure containing the small- 

 est portion of ammonia) yielded on its analysis 

 only 12 parts of gluten, whereaslOO parts grown 

 on the same field, but manured with human 

 urine (the manure containing the largest quan- 

 tity of ammonia) yielded the maximum of 

 gluten, viz. 35 parts.* 



From this it will be seen that it is perfectly 

 within the power of the agriculturist to make 

 his crops nutritious or otherwise. 



If manured with urine or with other ma- 

 nures, which will furnish a supply of this most 

 important ingredient, the grain will be nutri- 

 tious and heavy. If on the contrary this pabu- 

 lum is not supplied to the growing crop, the 



*Liebig. 



