CRYPTOGAMS 239 



What does this teach us regarding the effect of heat on 

 molds ? 



Why do canned fruits as a rule not become moldy? If 

 one should find mold in a fruit jar, what inference can be 

 made as to the method of canning? Open the jar in which 

 there is a good crop of mold and quickly plunge in a lighted 

 candle. Does it burn or go out ? What does this show as to 

 what is given off by molds ? 



For laboratory work, lay a slice of stale bread or some 

 slices of cold boiled potato on a dish. Dampen or add a 

 sponge saturated with water and cover with a bell jar. 

 When a good crop of mold has appeared, remove the bell 

 jar and examine the colony of plants. Note color, size, 

 smell, and general appearance of the plants. Notice the 

 tiny threads (hyphse) which form a delicate network all 

 over and through the bread. Look for other hypha3 which 

 stand up at right angles to the surface. How do these up- 

 right threads terminate? (Sporangium.) 



Observe these parts with a magnifier. How do the spo- 

 rangia differ in color ? How may old ones be distinguished 

 from young ones? 



Make mold cultures of all manner of food stuffs and com- 

 pare them. See if you can grow bread mold on cheese or 

 meat. Also the reverse. 



203. MOLDS 



Object. To show the development of different molds in 

 food materials. 



Apparatus. Several plates, bell jars or tumblers for covers, 

 and an assortment of foods, such as bread, cheese, orange peel, 

 banana, etc. 



