2 10 PLANT LIFE. 



examination under the microscope. Thus, scraping 

 the teeth with the end of a pencil will furnish a whitish 

 matter consisting chiefly of bacteria. A section of the 

 tubercles on clover roots, or a little cream left standing 

 for a day or two, will also show an abundance of 

 bacteria. 



Both Moulds and Yeasts belong to the Fungi. 

 Their action is, in many respects, very similar to that 

 of Bacteria. 



The spores of the Moulds Penicillium, Mucor, and 

 Aspergillus are exceedingly abundant in the air, and are 

 also capable of resisting great extremes of temperature. 

 These fungi, however, differ from bacteria in con- 

 sisting, not of single cells, but of long branching threads 

 which grow in every direction through the liquid 

 matter, or over the soil, upon which they are living. 

 They produce spores in extraordinary abundance. To 

 obtain these moulds, it is only necessary to put into 

 a saucer a little jam, fruit, or bread in water, and to 

 cover it with a tumbler. A white, greenish, or brown 

 mould will very soon develop, and will overspread the 

 whole of the material. It is only necessary to pick out 

 a little of this substance, and to examine it in water 

 under the microscope, to get a clear idea of the 

 abundance of the conidia or spores. 



They are produced on little upright stalks, which will 

 ensure the spores being caught and carried off by slight 

 currents of air. The three commonest fungus forms 

 are Mucor, Penicillium, and Eurotium. These moulds 

 break up vegetable and animal matter. A spore 

 germinates in a fruit solution, and grows out into 

 long branching threads, which explore the solution in 

 every direction. The fungus lives upon the sugars and 

 other matters, and breaks them up, producing carbonic 



