26 BOTANY. 



mucor the protoplasm has the same general appearance as in 

 spirogyra, its arrangement is very different. In the first place 

 it is plainly continuous throughout the tube. We do not see 

 the prominent radiations of strands around a large nucleus, but 

 still the protoplasm does not fill the interior of the threads. 

 Here and there are rounded clear spaces termed vacuoles, which 

 are filled with the watery fluid, cell-sap. The nuclei in mucor 

 are very minute, and cannot be seen except after careful treat- 

 ment with special reagents. 



53. Movement of the protoplasm in mucor. — While examin- 

 ing the protoplasm in mucor we are likely to note streaming 

 movements. Often a current is seen flowing slowly down one 

 side of the thread, and another flowing back on the other side, 

 or it may all stream along in the same direction. 



Exercise 1 2. 



54. Study of mycelium. — Use portions of the mould which have not become 

 black. These portions are the mycelium, mats of the fine colorless threads. 



Note the color of the threads, the absence of chlorophyll. To test this 

 place some of the threads in strong alcohol, let stand for some time. Does 

 the alcohol become colored ? 



Take some fresh threads and place them in the iodine solution. Remove 

 and rinse in water. What is the color ? 



Place fresh threads in some of the \% aqueous solution of eosin, and rinse 

 in water. Do the threads hold the color? Now immerse the same threads 

 in strong alcohol, then rinse in water, and place in the eosin solution for a 

 moment. Rinse in water. Do the threads now hold the stain? Why? 



Write out a complete account of the experiments and observations. 



Exercise 1 3. 



55. To obtain the mould from fruits. — This may be made a home exercise 

 if preferred. It is well whenever possible to get the pupils to do some of the 

 work of preparation. 



Let each pupil take half an orange or lemon, squeeze out the juice, and 

 leave it exposed in his living room through the day. At night place it 

 along with some pieces of bread in a glass tumbler, first putting a wet piece 

 of paper in the bottom of the tumbler. Cover the vessel with a piece of 

 glass. Keep in a warm room. Each day observe what appears, keeping 

 notes, and describing the appearance of the mycelium. Observe if the black 

 mould appears when the growth comes to fruit. 



