Exchange and Movements of Gases and Liquids. 53 



edge of the cover. Observe the action of the solution on the 

 cells. A few minutes later remove the salt and add distilled 

 water, and note the resumption of the original position of the 

 parts of the cells. The salt solution is more concentrated than 



Fig. 30. — Plasmolysis of Spirogyra. A^ normal turgid cells ; B, plasmolyzed cells. 



the sap of the cells. As a consequence, some of the water is 

 withdrawn from the cell (Fig. 30). 



I 48. Turgidity in an osmometer. — Soak a section of 

 dialyzer tubing in water for a few minutes, then pleat and tie 

 both ends after filling with moist sugar. Lay in a dish of rain- 



Fig. 31. — Glass cylinder filled with concentrated salt solution, and both ends 

 covered with parchment. After immersion in water it becomes turgid, and fluid 

 is forcibly expelled when the parchment is punctured. After Oels. 



water, and note condition a half hour later. If parchment tub- 

 ing is not procurable, tie convenient pieces of parchment or 

 bladder over the ends of a glass cylinder, such as a lamp chim- 

 ney, by means of cord, having first filled the cylinder with 

 moist sugar. The. parchment cell is soon distended by the 



