I 



YEASTS AND MOULDS. 1 7o 



Stab Culture. Radiating yellow or white processes spring from 

 the line made by the needle, those near the surface having oval 

 ends. 



Potatoes. The yeast form, develops as thick white colonies. 



Bread Mash. Snow-white veil over the surface. 



Pathogenesis. In man the parasitic thrush, or "white mouth, 1 ' 

 is caused by this fungus. In the white patches the spores and 

 filaments of this microbe can be found. Babbits receiving an 

 intravenous injection perish in twenty-four to forty-eight hours, 

 the viscera being filled with mycelia. 



True Moulds. Fliigge has made five distinct divisions of 

 moulds. It will, however, serve our purpose to classify those 

 to be described under three headings : Penicillium, J/wcor, and 

 Aspergillus, 



Penicillium Glaucum. 



Origin. The most widely distributed of all moulds, found 

 wherever moulds can exist. 



Form. From the mycelium, hyphse spring which divide into 

 basidia (branches), from which tiny filaments arise (sterigmata), 

 arranged like a brush or tuft. On each sterigma a little bead 

 or conidium forms, which is the spore. In this particular fungus 

 the spores in mass appear green. 



Growth. It develops only at ordinary temperatures, forming 

 thick grayish-green moulds on bread-mash. At first these ap- 

 pear white, but as soon as the spores form, the green predomi- 

 nates. Gelatine is liquefied by it. 



Mucor Mucedo. Next to the penicillium glaucum, this is the 

 most common mould. Found in horse dung, in nuts, and 

 apples, in bread and potatoes as a white mould. 



Form. The mycelium sends out several branches, on one of 

 which a pointed stem is formed which enlarges to form a globu- 

 'ar head, a spore-bulb, or Sporangium. The spore-bulb is par- 

 itioncd off into cells in which large oval spores lie. When the 

 spores are ripe a cap forms around the bulb, the walls break 

 down and the wind scatters the spores, leaving the cap or 

 " columella" behind. 



Growth. Takes place at higher temperatures on acid media. 



It is not Patfiogenic. 



