300 PHYSIOLOGY AT THE FAEM. 



vegetative energy. Sulphur is thrown off from the animal 

 body after oxidation in the form of sulphuric acid combined 

 with the common bases, as potassa, soda, ammonia. 



Phosphorus. Phosphorus does not manifestly exist free in 

 organic nature. It can be detected, however, in the nervous 

 substance of the animal kingdom, and in the proteine com- 

 pounds, fibrine and albumen. It exists abundantly, com- 

 bined with oxygen, in all the three kingdoms of nature. It 

 exists in the form of phosphates in small proportion, but 

 widely diffused throughout the rocks of the crust of the 

 earth. From the disintegration of such rocks it gets into the 

 soil of the earth, to supply the two organic kingdoms with 

 their proportion of phosphates. Phosphate of lime is known 

 under two mineral forms namely, apatite and phosphorite ; 

 which, though in some districts they constitute mountain- 

 masses, are not widespread over the earth. Phosphorus is a 

 far more abundant element in organic nature than sulphur, 

 and therefore deserves a proportionately greater attention in 

 the consideration of artificial manures and in the feeding of 

 animals. It has been said, though some doubt is cast on the 

 statement, that even sea -water contains phosphates. The 

 ashes of red wheat contain, according to Liebig, 94.44 per 

 cent of phosphates ; the ashes of white wheat, 91.47 per cent ; 

 the ashes of pease, 85.46 per cent ; the ashes of beans, 97.05 

 per cent of the same salts whence it follows that the ashes 

 of these several substances have phosphorus present in them 

 to the extent of from 1 5 to 20 per cent. 



Phosphorus is contained, probably free, in albumen and 

 fibrine. In the animal kingdom the phosphates hold a 

 prominent place among its saline constituents. If the phos- 

 phates in the living body amount to about one-fifth part of its 

 weight, as some calculations would intimate, then every human 

 body must contain several pounds of phosphorus. The phos- 



