l6 BOTANY. 



plus of water. Remove the seeds from the water and scatter them over the 

 paper. Place another sheet of wet filter paper over them, and if it is necessary, 

 in order to keep the seeds moist, scatter among 

 them a little damp absorbent cotton. Cover 

 with a glass or with an inverted vessel to pre- 

 vent too rapid evaporation of the moisture. Set 

 aside in a warm place, about 22° C. to 25° C. 

 (about 70°-8o° Fahr.). Look at the culture Fig. 6. 



every day to see that there is just the right Seedling of radish, showing root 



. hairs, 



amount of water to keep the seeds from drying, 



and also to see that there is not a surplus of water or the seeds will rot. 



When the roots have begun to appear from the seeds remove the upper 

 layer of paper and moss so that the root hairs can develop without interfer- 

 ence. When the young roots just back of the tip are covered with a downy 

 growth of colorless hairs, as in figure 6, they are ready for use. 



Demonstration 3. 



35. To prepare the root hairs for examination with the microscope. — 

 Hold the root between the thumb and finger (or in this position between two 

 thin pieces of elder pith to give it support). Then with a sharp razor, the 

 blade resting on the forefinger and the edge against the root in the region of 

 the root hairs, make a sliding cut across the root. Make several successive 

 similar cuts in such a way as to get thin cross-sections of the root with the 

 root hairs attached. Mount these sections in a drop of water on a glass slip 

 and cover with a clean circle cover glass. Or with the needles tease out 

 a small portion of the root with the root hairs attached. Tease apart the 

 tissues in a drop of water, being careful not to break off the root hairs, and 

 mount in water on a glass slip. Place the slip under the microscope and focus 

 the microscope on suitable root hairs for demonstration of the protoplasm. 

 Let each pupil be seated at the microscope for a few moments to observe the 

 protoplasm in the root hairs. 



Demonstration 4. 



36. Protoplasm in the root hairs. — Examining this preparation with the 

 aid of the microscope we see that each thread or root hair is a continuous 

 tube. It is a single plant cell which has become very much elongated and 

 free by pushing out its free end some distance from the other cells of the 

 outer portion of the root. Observe the boundary wall of the thread. This is 

 the cell wall. Within this the protoplasm is seen. It is colorless and very 

 granular, that is, numerous fmall granules of different sizes lie quite closely 

 together in a colorless slimy liquid. This is the protoplasm. It does not 



