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 hsema- 

 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 the 

 mouth there will 

 appear on it the 

 scrapings in the 

 e form of a white 



FIG. 12. A, diagram of a cell; w, cell wall with inclosed _j f "R 



cytoplasm; n, nucleus, consisting of nuclear membrane ^ " 



inclosing granular substance, in which are seen a move a little of 

 spherical nucleolus and irregular masses of chromatin* 



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



ceU division * 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. 



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