156 Muhlenbergia, Volume 5 



downward; whether moisture or gravity has the greater influ- 

 ence upon the direction of growth in roots; to illustrate the law 

 of osmosis; to discover whether water will readily pass through 

 the epidermis of roots; whether water will readily pass through 

 the walls of the root hairs; through what part of the root the 

 moisture travels upward; where roots increase in length; what 

 part of the root is able to turn; whether roots excrete acids; 

 where the stem grows in length; in what part of the stem the 

 sap passes upward; the path of the elaborated plant food in the 

 stem; whether cell turgor aids in keeping the leaves expanded; 

 whether tissue tension aids in holding petioles erect; whether 

 the absorption of water can cause change of position in parts of 

 plants; whether leaves transpire; whether water is given off by 

 the stomata; whether leaves can control transpiration; whether 

 more moisture is ever sent to the leaves than they can transpire; 

 whether plants respire; whether plants give off gases in sun- 

 light; to test the gas given off by plants in sunlight; where the 

 gas given off by plants in sunlight is obtained; whether sun- 

 light has any effect upon the formation of starch; whether chlor- 

 ophyll has any effect upon the formation of starch; whether 

 plants withdraw the starch made in the leaves. 



The book should have a wide field of usefulness in hi eh 

 school work, and no doubt will do much toward creating a last- 

 ing interest in the study of plant life. — A. A. HELLER. 



