386 MICROORGANISMS 



Thus, when we say that molds have caused an apple to decay, 

 we might describe more specifically what happens if we were 

 to say that the molds have digested and absorbed and grown on 

 the foods contained in the apple. We can not say that the 

 mold eats the apple for as we commonly use that term, it 

 involves chewing and swallowing and this the mold does not 

 do. In the light of this discussion of the way in which a mold 

 gets its food, can you suggest how it is that the delicate hyphae 

 of the mold are able to make their way through the solid pulp 

 of an apple? 



438. Methods of Spore Production. After you have studied 

 the mycelium of a given mold under the microscope, mount a 

 little of the portion of it which is just beginning to show spores 



and observe the character of the 

 structure which bears the spores. 

 The spores are generally borne 

 on vertical branches of the myce- 

 lium which extend some distance 

 above the SUB-STRATUM, or mass 

 of food, within which the main 

 body of the mycelium is grow- 

 T, 0ftK ing. At the top of this vertical 



FIG. 265. Aspergillus. r 



branch which is called a SPORO- 

 PHORE, the spores are borne in different ways in different kinds 

 of molds (see Fig. 264). In MUCOR, the common black bread 

 mold, a cross wall cuts off a cell at the tip of the sporophore. 

 This cell grows larger and assumes a spherical form. At the 

 same time, the cross wall bulges into this uppermost cell and 

 forms a smaller sphere within the larger one. Next, the pro- 

 toplasm of the outside cell breaks up into numerous spores. 

 Such a spore-producing organ is called a SPORANGIUM. The 

 accompanying figures illustrate the manner in which some 

 other common molds produce spores (Figs. 265, 266, and 267) . 

 Note the countless number of spores that you get on your 

 microscope slide from a very small quantity of the material. 

 Remembering that these spores are always borne up in the air 



