GENERAL PHYSIOLOGY 259 



Compare the fluidity of the animal and plant cells provided. Does 

 the nucleus differ from the cytoplasm in optical properties? Try 

 the effect of acetic acid if the nucleus is not clearly distinguishable 

 in the living condition. What evidence can you obtain that there 

 is an external living membrane present? Compare the plant and 

 animal cells in this regard. 



B. If there is movement within the cells describe this "cyclosis" 

 in detail, making diagrams to show the directions in which the 

 granules move. Does the movement follow definite lines? Com- 

 pute the rate in millimetres per second of the protoplasmic move- 

 ment in Elodea, or Tradescantia at room temperature, by means of 

 an ocular micrometer and stopwatch. It is a rule that the speed 

 of chemical reactions is doubled with each rise of 10 C. (Van't 

 HofFs rule). This is expressed by the equation, Qi = 2. For a 



10 



/ IT-\'- 



range of less than 10 C. the following formula is used : Q 



where KI = initial rate, and K 2 the final rate of the reaction/ ti = 

 the original temperature, and t 2 the final temperature. Does living 

 protoplasm obey this rule? Plot a heat curve containing at least 

 four points for (1) a plant cell exhibiting striking protoplasmic 

 movement, (2) contraction of the vacuoles in the paramecium, and ^ 

 (3) the pulsations of the dorsal blood vessel of the earthworm. 'i 

 What is the highest temperature from which the cells will recover cS*- 

 after an exposure of 3 minutes? What changes in the appearance '5 ' 

 of the protoplasm occur above this temperature? (Consult Bayliss " j*- 

 General Physiology pp. 41-45). j*^ 



C. What is the effect of various concentrations (N/10, N/100,^ t 

 N/1000, etc.), of acids (e.g., acetic, HC1), bases (NH 4 OH, NaOH), " 

 salts (NaCl, CuSO 4 , HgCl 2 ), anaesthetics (alcohol, ether, chloroform) 

 sugar, iodine, etc., on the movements of protoplasm and on the 

 physical state of the protoplasm? In what ways do Stentor, 

 Paramecia, and Amoeba each attempt a defense against a harmful 

 agent? Can you give an explanation of this action on purely 

 physical or chemical (non-anthropomorphical) grounds? 



D. Plasmolysis is the shrinking of the protoplasm in a plant 

 cell from its cellulose wall. Is the cellulose wall living? What is 



