MANURES 87 



was taken up by the blood. All tliat remains to be 

 examined is the eartliy matter in the blood, which 

 would have become ashes, if the hay had been 

 burned. The readily soluble part of this earthy mat- 

 ter passes into the bladder, and forms the earthy 

 parts of urine. The more insoluble part passes the 

 bowels, in connection with the dung. 



If any of the food taken up by the blood is not 

 returned as above stated, it goes to form fat, muscle, 

 hair, bones, or some other part of the animal, and as 

 he is not growing (not increasing in weight) an 

 equivalent amount of the body of the animal goes to 

 the manure to take the place of the part retained.* 



We now have our subject in a form to be readily 

 understood. We learn that when food is given to 

 animals it is not j^^^-i out of existence, but is merely 

 changed in form / and that in the impurities of the 

 breath, we have a large portion of those parts of the 

 food which plants obtain from air and from water ; 

 while the solid and liquid excrements contain all that 

 was taken by the plants from the soil andfrom manures. 

 The Solid Dung contains the undigested parts of the 



food, the more insoluble 

 parts of the ash, and the 

 nitrogenous matters which 

 have escaped from the di- 

 gestive organs. 



* This account of digestion Is not, perhaps, strictly accurate in 

 a physiological point of view, but it is sufficiently so to give an 

 elcmentaiy understanding of the character of excrement as 



