HISTOLOGICAL STUDIES 



XXII. PARTS OF A CELL. 



Apparatus. Scalpel, compound microscope 1 with two-thirds and 

 one-sixth inch objectives and one inch ocular, glass slides and cover 

 glasses, piece of filter paper, methyl green or Delafield's haema- 

 toxylin. 2 



Directions. Sterilize the scalpel by holding it in boiling 



water, then scrape 

 the inside of the 

 cheek lightly with 

 the blade. When 

 the scalpel is re- 

 moved from 

 mouth there 

 appear on it 

 scrapings in 



e r 



FIG. 12. A, diagram of a cell; w, cell wall with inclosed 



cytoplasm; n, nucleus, consisting of nuclear membrane S 6 CL 1 m 6 n t . 

 inclosing granular substance, in which are seen 

 spherical nucleolus and irregular masses of chromatin; 



a, centrosome; B-F, changes that take place during 

 cell division. 



the 

 will 

 the 

 the 



a white 

 Re- 

 move a little of 

 this sediment and 



mount in a drop 

 of water on the slide. Cover with the cover slip and ex- 

 amine with the two-thirds objective (low power). In focus- 



1 Bausch & Lomb and the Spencer Lens Co. furnish at request a pamphlet 

 describing all the parts of the microscope and method of handling the instru- 

 ment. 



2 For the preparation of these stains consult any manual of microscopy. 

 Lee's "Vade Mecum" is recommended. 



