GENERAL MORPHOLOGY 



23 



of nucleus, cytoplasm, and a wall which is probably a simple 

 superficial condensation of the protoplasm. The ordinary 



' 6 



FIG. 1. Microscope: A, ocular or eye-piece; B, objective; C, stage; D, 

 "iris" diaphragm; E, reflector; F, coarse adjustment; <?, fine adjustment; 

 H, substage condensing apparatus; /, nose-piece. 



animal or vegetable single cell 1 contains an easily distinguish- 

 able body, usually central, called the nucleus, whose function 



1 See frontispiece for an example of cell. Nearly all living cells are com- 

 parable to these leukocytes. 



