10 



HUMAN PHYSIOLOGY 



of sweetbread juice. Hence the relative importance 

 of cells is a point to be kept in mind, although we 

 must not lose sight of the fact that all cells are in 

 their way necessary and important, each discharging 

 its own duty in the maintenance and upkeep of the 

 frame of which it forms part. The work of cells 

 is identical with the work of the body at large. 

 They may be said to represent the workmen of the 

 frame whether their labour is devoted to supervising 

 its nutrition, to governing its interests, or to assist- 

 ing in building up the bodily tissues. Every- 

 thing that is made in the body for the body's use, 

 secreted or manufactured in fact from the blood as 



Fig. 5. CELLS 

 In which the nerves of taste end, 



the raw material, has to be regarded as representing 

 the work of cells. In the earlier stages of bodily 

 development the whole frame is represented by a 

 mass of cells. Where strong structures in the 

 shape of bone, muscle-fibres, ligaments and the like 

 have to be developed, we meet with such structures 

 directly originating from cells themselves. The 

 broad view which may be taken therefore of the 

 constitution of the human body is that of regarding 

 it as a really compound, or, as we might term it, 



