GENERAL BIOLOGY 



2. In prepared sections through the root-tip of an onion ob- 

 serve the shape and size of the cells. Draw about 10 adjacent cells. 

 Having found one or more complete cells with round nucleus ob- 

 serve and make a drawing about 2 inches in diameter of a single 

 cell showing the following parts: i. Cell Membrane. 2. Nucleus. 

 3. Cytoplasm (protoplasm surrounding nucleus). In the nucleus 

 observe: 4. Nuclear Membrane. 5. Nucleolus. 6. Chromatin (stained 

 granular part of nucleus). 7. Achromatin (unstained part of nu- 

 cleus). 



B. ANIMAL CELLS. 



1. With the handle of a scalpel gently scrape the inside of 

 your lip or cheek and mount the scrapings in a drop of water. 

 Draw several cells. Run a drop of aceto-carmine under the cover 

 glass by placing the drop on one side of the cover and applying 

 a bit of filter paper to the other side. The nucleus stains deeply 

 owing to the fact that it contains chromatin. Draw one cell show- 

 ing nucleus, cytoplasm, and cell-membrane; making the drawing 

 about 2 inches in diameter. 



2. In similar manner observe the cells and cell structures in 

 prepared slides of the skin of a frog. 



2. Mount a drop of frog's blood and examine under the low 

 power and then under the high. Draw several of the red, also of 

 the white, corpuscles. 



II. CELL FUNCTIONS. 



Each cell performs all the fundamental functions of life it 

 nourishes and reproduces itself, is contractile and sensitive, 

 though some cells are devoted more exclusively to one of these 

 functions than to the others (Specialization). In this place we 

 study only the functions of reproduction and movement. 



i. CELL REPRODUCTION. All cells reproduce by division; the 

 nucleus first divides, in one of two ways, after which the cell body 

 constricts into two. Nuclear division occurs by the indirect pro- 

 cess (Mitosis) or by the direct process (Amitosis). 



(i). Indirect Nuclear Division (Mitosis). 



In prepared slides of the growing root- tip of the onion observe 

 nuclei in the following stages of division : 



(a) Early Phophase, in which the nucleolus has disappeared 

 and the chromatin granules have united to form threads; (b) Late 



