2 2 ELEMENTS OF MAMMALIAN ANATOMY 



The different relative arrangements of these anatomic ele- 

 ments together with their morphology, permit one to know 

 from what organ any particular section of tissue under con- 

 sideration has been taken. 



Fig. II. — Photomicrograph of Fibers of Voluntary Muscle, X loo. 

 Note the finer threads of connective tissue. 



These ultimate units of structure are still further resolved 

 into parts by the chemist, who has show^n that they are com- 

 posed largely of carbon, hydrogen, oxygen, and nitrogen. 

 Since there can be no energy developed in the body without 

 the breaking dow^n of the complex organic compounds stored 

 up by the cells or else by the destruction of the cells them- 

 selves, it is plain that they must have their losses replaced in 



