372 NUTRITION. 



chloride of sodium, this substance modifying and regulating 

 the processes of absorption and probably of assimilation. 

 In addition, however, we find the chlorides as constituent 

 parts of every tissue and organ of the body, and so closely 

 united with the nitrogenized principles, that they cannot be 

 completely separated without incineration. Those inorganic 

 matters, the function of which is so marked in their passage 

 through the body, are found largely as constituents of the 

 fluids, and are less abundant in the solids. They are con- 

 tained in quantity, also, in the liquid excretions ; and any 

 excess over the amount actually required by the system is 

 thrown off in this way. Other inorganic matters are espe- 

 cially important as constituent parts of the tissues, and are 

 more abundant in the solids than in the fluids. Examples 

 of principles of this class are the salts of lime, particularly 

 the phosphates. These are also in a condition of intimate 

 union with organic matter, and accompany these principles 

 in all of their so-called vital acts. 



If we except certain simple chemical changes, such as the 

 decomposition of the bicarbonates, the inprganic elements of 

 food do not necessarily undergo any modification in the pro- 

 cess of digestion. They are generally introduced already in 

 combination with organic matter, and accompany it in the 

 changes which it passes through in digestion, assimilation 

 by the blood, deposition in the tissues, and the final trans- 

 formations that result in the various excrementitious mat- 

 ters ; so that we find the inorganic principles united with the 

 organic matter of the food as it enters the body, and what 

 seem to be the same principles in connection with the or- 

 ganic excrementitious matters; but between these two 

 extremes, are the various operations of assimilation and dis- 

 assimilation, from which inorganic matter is never absent. 

 We have already referred to these facts so often, under the 

 heads of proximate principles, alimentation, digestion, and 

 excretion, that it is unnecessary, in this connection, to dis- 

 cuss them more fully. 



