HUMAN PHYSIOLOGY. 



organs of lower animals. This experimental knowledge corrected 

 by a study of the clinical phenomena of disease and the results of 

 post-mortem investigations, forms the basis of modern human 

 physiology. 



CHEMIC COMPOSITION OF THE HUMAN 

 BODY. 



Since it has been demonstrated that every exhibition of functional 

 activity is associated with changes of structure, it has been apparent 

 that a knowledge of the chemic composition of the body, not only 

 when in a state of rest, but to a far greater degree when in a state 

 of activity, is necessary to a correct understanding of the intimate 

 nature of physiologic processes Though the analysis of the dead 

 body is comparatively easy, the determination of the successive 

 changes in composition of the living body is attended with many 

 difficulties. The living material, the bioplasm, is not only complex 

 and unstable in composition, but extremely sensitive to all physical 

 and chemic influences. The methods, therefore, which are em- 

 ployed for analysis destroy its composition and vitality, and the 

 products which are obtained are peculiar to dead rather than to 

 living material. 



Chemic analysis, therefore, may be directed 



1. To the determination of the composition of the dead body. 



2. To the determination of the successive changes in composition 

 which the living bioplasm undergoes during functional activity. 



A chemic analysis of the dead body, with a view to disclosing 

 the substances of which it is composed, their properties, their inti- 

 mate structure, their relationship to one another, constitutes what 

 might be termed CHEMIC ANATOMY. An investigation of the living 

 material and of the successive changes it undergoes in the per- 

 formance of its functions constitutes what has been termed CHEMIC 

 PHYSIOLOGY or PHYSIOLOGIC CHEMISTRY. 



By chemic analysis the animal body can be reduced to a number 

 of liquid and solid compounds which belong to both the inorganic 

 and organic worlds. These compounds, resulting from a proximate 

 analysis, have been termed proximate principles. That they may 

 merit this term, however, they must be obtained in the form under 



