78 EXCREMENTS AND URINE. 



foundation of our inquiries, if the results ascertained 

 by practical experience and experiments are destined 

 to arrive at clearness, connection, and certainty. 

 What has been already brought to light concerning 

 these points by chemical investigations is in mani- 

 fold respects still incomplete and defective ; never- 

 theless we must be contented with what is incom- 

 plete, until something more perfect has been pro- 

 duced. Whatever is known will be communicated 

 in the following sections. 



1. Origin of Animal F^ces. 



Here is a potato ; of what does it consist, and 

 what alterations must its constituent elements un- 

 dergo when it is used as fodder for cattle ? The po- 

 tato has been subjected, one knows not how often, 

 to chemical examination, and its constituent parts 

 are perfectly known. It has been found to contain : 



Proximate Constituents. Ultimate Elements. 



Starch, Vegetable Fibre, Carbon, Hydrogen, Oxy- 

 Albumen. gen. Nitrogen. 



Mineral Substances Potash, Lime, Silica, 



(Ashes). Phosphoric Acid, etc. 



The potato, as well as the greater number of other 

 substances employed in foddering cattle, has been 

 already analyzed, and in the same manner the sepa- 

 rate constituents of the bodies of these animals are 

 very accurately known. If now the composition of 

 the food is compared with that of the animal body, 

 we find, that, of the proximate constituents of plants. 



