BALANCE BETWEEN THE INGESTA AND FINAL PRODUCTS. 421 



For the cow, therefore, every 100 parts of the elements of 

 the food are distributed in the following proportions in the 

 excreta : 



It will be unnecessary to consider at the present time the con- 

 clusions to be drawn from these experiments, partly because they 

 are self-evident from a mere inspection of the table itself, and 

 partly because we shall revert to them at a future page, when 

 we shall enter upon the consideration of similar experiments. 



Valentin has also directed his attention to the distribution of 

 the salts in the metamorphosis of matter, for which purpose he 

 instituted a comprehensive series of experiments on a horse. These 

 experiments yielded several interesting results in regard to the 

 resorption of certain mineral substances in the intestine : it was 

 found that lime, phosphoric acid, and the alkaline salts were pre- 

 sent in great abundance in the urine (having been absorbed during 

 digestion) ; but that the magnesia occurred only in very small 

 quantities. In the ash of the excrement the phosphate of magnesia 

 was to the phosphate of lime in an inverse ratio to that which 

 occurred in the food, because 60*23f of the magnesia, which had 

 been absorbed, was again eliminated with the solid excrements, 

 whilst only about 25 g- of the absorbed lime was again given off with 

 the faeces. (Hence arise the frequent intestinal concretions observed 

 in herbivorous animals.) 



A mare whose weight was 935 Ibs., and her age four years, 

 consumed daily for nutrition and growth, and for other excretions 

 than the faeces and urine, 2'025 ounces of lime, 0*125 of an ounce 

 of magnesia, 0*74 of an ounce of silica, 0*035 of an ounce of 

 chlorine, 0'64 of an ounce of sulphuric acid, 19*25 ounces of phos- 

 phoric acid, and 0*76 of an ounce of alkalies. Thus, too, a tolerably 

 large proportion of the silica, which had been contained in the food, 

 could not be again found in the excrements and the urine. Of the 



