APPENDIX I. T1 
(6) To show the necessity of. 
Place an actively growing alga in the nutrient solution 
(Experiment 2) with the potassium nitrate omitted. A second 
quantity of alga is to be placed in the nutrient solution com- 
plete. Compare and explain results after a few days. 
II. METABOLISM. ° 
EXPERIMENT 8. TO SHOW TURGOR AND EXPLAIN FOOD 
ABSORPTION (Osmosis). 
(a) Egg experiment. 
Carefully remove the shell from the larger end of an egg, 
exposing a considerable area of the membrane. Drill a hole 
into the smaller end and insert a glass tube, being sure that it 
enters the yolk. Thoroughly seal with wax where the tube 
enters the shell to exclude air. Now place the larger end of 
the egg in a suitable vessel of water so that the latter will 
cover the exposed membrane. Support the tube in any conven- 
ient way. The tube ought to be two or three feet in length. 
Observe and explain the rise of the yolk in the tube. 
(6) Raisin. 
Place raisins in water and observe that they swell and be- 
come several times larger than at first. Why? 
(c) Seeds. 
Place beans in a thin test-tube (or better use a thin-walled 
glass vial with screw top) and then fill the tube with water; 
securely tie in a cork, and examine the next day. Explain the 
wrinkling of the seed at first, and later the smoothness of the 
seed and the breaking of the tube. 
EXPERIMENT 9. TO SHOW THE CAUSE OF FLACCIDITY 
(Wilting). 
(a) Into a 5 per cent solution of common salt place some 
longitudinal sections of a fresh rhubarb petiole, or any other 
