PROBLEM 90 113 



NOTE. Some of these threads reach down into the bread and act as roots, di- 

 gesting and absorbing nourishment. These are called rhizoids. Many of the 

 hyphae are prolonged into tiny upright threads, bearing at the top a little ball. This 

 is called the sporangium. 



With the low power of the microscope the structure of a 

 sporangium may be made out. The dark-colored ones are full 

 of ripe spores, which may be seen by lightly tapping the cover 

 slip over the slide. How do the spores get out of the sporan- 

 gium"? Try to find some young sporangia and note the differences 

 in size and color between them and the older ones. 



Conclusion. 1. How does bread mold get its food? 



2. How do you know that it cannot manufacture its own food ? 

 Explain. 



3. Have you seen any other kinds of molds on foods? If so, 

 on what foods? 



4. What effect do molds have on food ? 



5. What are the spores on bread mold for? 



6. What effect do their size and numbers have on the spread of 

 the mold? 



Drawings. Draw a series of sporangia as seen under the low 

 power. 



Froblem, 90 : What is fermentation and what causes it ? 



Materials. Fermentation tube, yeast, molasses, test tube, 

 Erlenmeyer flask, limewater, absorbent cotton, cork, and delivery 

 tube. 



Method. Carefully fill a fermentation tube with a mixture of 

 molasses, water, and a little piece of compressed yeast cake. Plug 

 the open end with absorbent cotton. Put in a warm place over 

 night. Partly fill an Erlenmeyer flask with a mixture of molasses, 

 water, and compressed yeast cake. Close the flask with a stopper 

 fitted with a delivery tube which leads into a test tube filled with 

 limewater. 



Observations. What has happened to the filled end of the 

 fermentation tube? How do you account for this? Smell the 

 contents of the flask after a day or two. What is this odor? 

 What has happened to the limewater? 



HUNTER LAB. PROB. 8 



