14 HUMAN PHYSIOLOGY 



things that are inorganic or non-living in their 

 nature. A geranium growing in a pot illustrates 

 equally with man the necessity for a constant food- 

 supply. The plant will draw from the air so much 

 carbonic acid gas, which is absorbed by its leaves. 

 By its roots it will take up from the soil water, 

 minerals, and also a certain amount of ammonia; 

 these items constituting the food of the green plant. 

 The failure to supply any of these items will result 

 in the death of the plant from a want of nourish- 

 ment, and if we turn to the animal the same remark 

 applies. Its food is certainly different from that of 

 the plant, but whatever be the kind of nourishment 

 necessary for the animal, that nutriment must be 

 supplied, otherwise, like the plant deprived of water 

 and other food, the existence of the animal will 

 assuredly come to an end. 



WHY WE EAT OUR DINNER. Associated with this 

 demand for food, another consideration crops up in 

 the shape of the inquiry why food-taking should 

 represent a necessary duty of the living being at all. 

 From a social point of view we might argue that had 

 we been differently constituted, a very large number 

 of our fellow-beings might find existence a somewhat 

 easier matter than it proves to be. There is a con- 

 stant struggle on the part of many human beings to 

 obtain food ; hence, if the duty of getting food were 

 removed, their existence might prove a less arduous 

 period than is represented to-day. It is easy to show 

 that the inexorable laws of nature, which have to be 

 obeyed lest the penalty of disease and death come 

 upon us, are founded upon a very plain and distinc- 

 tive feature of the living constitution. An answer 

 to the question, " Why do we want our dinner?" is 

 perhaps not so easily or satisfactorily supplied as 



