PART I 



METABOLISM 



THE combustible constituents of our body continually 

 undergo chemical changes, in that they are burned by the 

 inhaled oxygen. 



The products of combustion are removed from the tissues, 

 in which the combustion takes place, by the circulating 

 blood and lymph; one of these products, the carbonic acid 

 gas, is excreted from the body by the lungs; the other 

 products, by glands. 



That the body may continue to exist, new material for 

 combustion must be supplied to it from without. This is 

 effected by the partaking of nourishment which is made 

 absorbable by digestion, and, after absorption, supplied to 

 the tissues by the blood and then assimilated. 



Metabolism, therefore, includes the following parts of 

 physiology : 



1 . The chemical constituents of the body and their physio- 

 logical importance. 



2. Blood, the gases of the blood and respiration, circula- 

 tion of the blood, respiratory movements, lymph. 



3. Secretions. 



4. Nutrition, alimentary principles, food, digestion, ab- 

 sorption and assimilation of the digested food. 



5. Survey of metabolism as a whole. 



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