CELLULAR ORGANIZATION OF PROTOPLASM 1 

 B. Animal Tissues 



1. Mount a small piece of the shed outer layer (epidermis) of Frog skin, 

 which has previously been stained. Note that the general structure of 

 these animal cells is the same as that of the plant cells. Identify cell 

 wall, cytoplasm, and nucleus. Remember that each cell is entirely 

 enclosed in a cell wall through which you are viewing the cytoplasm and 

 nucleus. Examine the preparation, with both the low and the high power, 

 and draw about 10 adjacent cells to show their structure and arrangement. 



2. With the end of the handle of the scalpel or your finger gently scrape 

 the inside of your cheek. Mount the scrapings and examine the prepara- 

 tion with both the low and the high power. You should find numerous 

 irregular shaped cells which have been detached from the lining. Draw, 

 under high power, several cells of different shapes. 



3. Carefully remove the cover glass from the preparation you have been 

 studying and stain the cells by adding a drop of acetic carmine. Replace 

 the cover glass, examine under the high power, and observe the changes 

 which have taken place as a result of the stain. It will be noted that 

 the nuclei of the cells stain more heavily than the cytoplasm. Make a 

 drawing, about one inch in diameter, of a single cell showing the general 

 structure as observed. 



4. Examine a permanent preparation of the skin of the Frog or of some 

 other Vertebrate, and note several layers of epidermal cells on the upper 

 surface. These range in shape from the cuboidal or the columnar type 

 lying below, to the flattened type above which forms the outer surface. 

 Make a drawing of a portion of the epidermis to show the cell structure 

 and arrangement. 



5. Mount a drop of Frog's blood which has been diluted with normal 

 salt solution. Examine the preparation under the low power and note the 

 general appearance and structure of the numerous, disc-shaped blood cells 

 (red corpuscles) floating in the plasma. 



6. Examine the preparation with the high power, gently tapping the 

 cover glass from time to time in order to set the cells in motion so that you 

 may see them as solids with their three dimensions. Draw a number of the 

 cells as seen from various aspects. 



1 B. pp. 3-8. 

 249 



