258 APPLIED BIOLOGY 



suddenly shows molds. The rubbers have softened, or loosened, or 

 become moist, so that mold hyphae have grown into the jars. Hence 

 jars of fruit should be kept in a cool and dry pjace unfavorable for 

 growth of molds. Aside from this relation to molds, rubbers of fruit- 

 jars also prevent evaporation of the fruit juices. 



Rotting of fruit has been mentioned as due to molds. Take a 

 perfect apple and inoculate it by sticking in several places with a 

 needle which has been plunged into a very rotten apple. Take 

 another perfect apple, bruise the skin on one side, and place it in a 

 covered can or box in contact with a rotting apple. In both cases be 

 sure there is moisture the apples may be kept on wet cloth or cotton. 

 Take another perfect apple, gently rub the skin in several places 

 with a smooth stick which has been plunged into a rotting apple, so 

 as to distribute spores over the uninjured surface of the apple, 

 and set this one in a cool and dry place for comparison with the others. 

 What are the conclusions regarding apples infecting each other? 

 Why should injured apples be separated from perfect ones before 

 packing ? Why are apples bored by worms (larvae of codling moth) 

 and "windfalls" so liable to decay? Why should fruit-cellars be 

 cool and dry? Since the spores usually mature after rotting is 

 well advanced, it is evident that removal of windfall fruits, as by 

 pigs living in orchards, prevents the enormous multiplication and 

 distribution of spores of various molds which injure fruit. 



Instead of pieces of bread called for in above experiments, 

 a dilute sugar solution (three or four tablespoonf uls of sugar in a pint 

 of water) may be used. Or use some diluted juice from canned 

 fruits. It is interesting to prepare some tubes with the sugar 

 solution and try all the experiments both with sugar and bread. 

 Of course, any other organic material on which molds grow could 

 be used in place of bread or sugar solution. 



Write a short essay on "Molds in Relation to Preservation of 

 Food for Human Use." Read Section I in Conn's "Bacteria, Yeasts, 

 and Molds in the Home." 



246. Economic Relations of Molds and their Allies. 

 Many fungi popularly known as molds, mildews, rusts, rots, 

 blights, smuts, scabs all of them more or less closely related 

 to the common molds which grow on bread and other foods 

 are very important economically, because of their injurious 

 effect on many cultivated plants. The following are common 

 examples. 



