32 THE HUMAN MECHANISM 



The muscle and the gland consist of cells, just as all the 

 branches of the military service the infantry, the cavalry, 

 the artillery, the engineers, etc. consist of men. The cell 

 is the anatomical or fundamental unit of these organs, as the 

 soldier is the fundamental or anatomical unit of the army; 

 in both cases the anatomical units, differing in equipment 

 and training, perform different kinds of work, yet have the 



FIG. 22. Section of a portion of a salivary gland (magnified 500 diameters) 



After Kcelliker 



The duct d divides into the two branches d' and d" , one of which ends in the 



alveoli, a, a. Neighboring alveoli, a', a', whose ducts are not in the plane of the 



section, are also shown. In some cells the section does not include the nucleus, 



which would be in the preceding or the succeeding section 



same essential structure ; and the cells are combined into 

 brigades, divisions, or corps, as tissues and organs ; they make 

 of the body an army organized to fight its way through the 

 vicissitudes and against the obstacles of life. 



5. The structure of the biceps muscle. The biceps muscle 

 is familiar as the mass of flesh lying on the front of the 

 upper arm and bulging somewhat when the arm is bent at 

 the elbow, especially when one "feels his muscle" or when 

 a weight is being lifted by the hand. Figure 23 shows this 

 muscle with the bones to which it is attached. It consists of 



