42 PRELIMINARY STUDIES. 



plant until the following season. It then develops by 

 cell division into a new thread of the ordinary sort. 



The Molds. 



Keep pieces of moist bread under bell glasses until a 

 white growth develops on them. Allow this to mature ; 

 the maturity will be indicated by the formation of little 

 black knobs of microscopic size. Examine some of these 

 knobs under the microscope. Each knob is a sporangium 

 filled with spores. The spores are of the type known as 

 gonidia. When ripe sporangia are mounted in water for 

 examination under the microscope, they burst and scatter 

 their spores. By watching the cultivation and taking 

 young sporangia, better specimens may be obtained. 

 Draw a sporangium and some of the spores. 



The plant is one of the Mucors. It is a saprophyte, i.e., 

 it lives upon decaying organic matter. It contains no 

 green coloring matter, chlorophyl, arid has no power to 

 assimilate mineral matters from the substratum on which 

 it grows or carbon from the air around. Its mode of life 

 is in a measure like that of the lower animals. 



All ordinary plants which contain the green coloring 

 matter, chlorophyl, are holophytes, i.e., their mode of life 

 is wholly characteristic of plants. Unlike the saprophytes 

 and animals they have the power to assimilate mineral 

 matters from the soil or water in which they grow and 

 carbon from the carbon dioxide of the air. This power 

 resides in the green coloring matter, chlorophyl. 



frotococcus. 



1. Obtain some of the green incrustation which is so 

 conspicuous in wet weather on old trees, fences, and walls. 

 It is Protococcus. Examine under high power. It is a 



