ASHES OF FOOD OBTAINED FROM SOILS. 169 



.hat in the food. The mixture of" these indigestible materials 

 with the secretions may be compared to the smoke and soot 

 produced when food is imperfectl}- burned in a common fire- 

 place. 



It has been shown, by an examination of faeces and of urine, that 

 the mineral ingredients of the food, the alkalies, salts, and silica, 

 are eliminated in these excrements. Urine contains all the solu- 

 ble mineral substances of the food, while the faeces contain the 

 ingredients insoluble in water. As the food is burned in the 

 body just as it would be in a fire-place, the urine may be said to 

 contain the soluble salts of the ashes, and the faeces the insoluble 

 salts. — (See Appendix.) A horse 



CONSUMES Of INGREDIENTS OF THE SOIL — AND THE EXCREMENTS RETURN — 



Ounces of Ashen. Ounces of Ashes. 



In l51bs. hay* . . . IS'01 ) In urine . 3*51 



In 4-54 oats 



In its drink 



1SC1 ) In urine . 3 # 51> 01 .o-, 



3-40 > 21-40 In feces . 18.36) "' V 

 0-42 > 



A COW — 



In 30 lbs. of potatoes . . 6*67) In urine . 12*29 ) 



In hay . ... 20-20 S 28*47 In faeces . 1636 V 30*45 



In its drink . . J (i ) In milk . 1*S0) 



These analyses show, as nearly as can be expected from ex- 

 periments of this kind, that all the constituents of the ashes of 

 the food are again obtained, without alteration, in the solid and 

 liquid excrements of the horse and cow. The action produced 

 upon our fields, by the liquid and solid excrements of animals, 

 ceases to be mysterious or enigmatical, as soon as we have at- 

 tained a knowledge of their mode of origin. 



The mineral ingredients of food have been obtained from our 

 fields, having been removed from them in the form of seeds, 

 of roots, and of herbs. In the vital processes of animals, the 

 combustible elements of the food are converted into compounds 

 of oxygen, while the urine and the fasces contain the constituents of 

 the soil abstracted from our fields ; so that, by incorporating 

 these excrements with our land, we restore it to its original state 

 of fertility. If they are given to a field deficient in ingredients 

 necessary for the growth of plants, it will be rendered fertile for 

 all kinds of crops. 



• Boussingnult, A finales de Chimie et de Physique, \xxi 

 



