CHAPTER IX. 



THE TRUE FUNGI (My corny cefes). 



THE great majority of the plants ordinarily known as fungi 

 are embraced under this head. While some of the lower forms 

 show affinities with the Phycomycetes, and through them with 

 the algae, the greater number differ very strongly from all 

 green plants both in their habits and in their structure and 

 reproduction. It is a much-disputed point whether sexual 

 reproduction occurs in any of them, and it is highly probable 

 that in the great majority, at any rate, the reproduction is 

 purely non-sexual. 



Probably to be reckoned with the Mycomycetes, but of doubt- 

 ful affinities, are the small unicellular fungi that are the main 

 causes of alcoholic fermentation; these are the yeast fungi 

 (Saccharomycetes). They cause the fermentation of beer and 

 wine, as well as the incipient fermentation in bread, causing it 

 to "rise" by the giving off of bubbles of carbonic acid gas 

 during the process. 



If a little common yeast is put into water containing starch 

 or sugar, and kept in a warm place, in a short time bubbles of 

 gas will make their appearance, and after a little longer time 

 alcohol may be detected by proper tests ; in short, alcoholic 

 fermentation is taking place in the solution. 



If a little of the fermenting liquid is examined microscopically, it will 

 be found to contain great numbers of very small, oval cells, with thin cell 

 walls and colorless contents. A careful examination with a strong lens 

 (magnifying from 500-1000 diameters) shows that the protoplasm, in 

 which are granules of varying size, does not fill the cell completely, but 

 that there are one or more large vacuoles or spaces filled with colorless 



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