HISTOLOGICAL STUDIES 



XXII. — ^Parts of a Cell. 



Apparatus. — Scalpel, compound microscope^ 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 the 

 mouth there will 

 appear on it the 

 scrapings in the 

 ^ f '' form of a white 



Fig. 12. — A, diagram of a cell; w;, cell wall with inclosed -i • + P 



cytoplasm; n, nucleus, consisting of nuclear membrane fc»^^Ainun Ir. JXid- 



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

 spherical nucleolus and irregular masses of chromatin; 



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



^ 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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