YEASTS IIQ 



tion, contains the spores within its interior. The M. mucedo has thick silver-gray 

 mycelium, with large sporangia, 150 ft in diameter, containing oval spores, 5 X Qj". 

 The M. corymbifer, which has been reported from a generalized infection, con- 

 sidered as typhoid, shows a snow-white mycelium. The sporangia are 20 to 4o/x 

 and the spore about 3jw in diameter. 



Rhizopus niger has a columella which becomes distorted into a mushroom shape 

 after the spores have been discharged from the sporangium. This mould has been 

 considered as the cause of a mycosis of the tongue. 



Ascomycetes. -In this order are included many of the parasitic 

 moulds. The most distinctive characteristic is the formation of asco- 

 spores in an ascus (little sac). It is an enlarged extremity of a hyphal 

 branch in which a definite number of spores, usually eight, is formed. 

 The ascus usually ruptures at its tip. Other members of the order are 



FIG. 39. Yeast cells. Saccharomyces cerevisiae. (Coplin.) 



formed from hyphae by the separation of cells in succession from the 

 free cells. The mycelium is septate. 



The order is divided into those with naked asci (Gymnoascus) and those having 

 a perithecium or investing layer about the ascus (Carpoascus). 



Belonging to the suborder Gymnoascus we have i. the family of Saccharomycetes, 

 which reproduce by budding and in which the asci are without any semblance of a 

 sheath, and 2. a family in which there is an indication of the formation of a peri- 

 thecium this may be termed the Gymnoasceae family. 



Saccharomycetes. There are three genera: Saccharomyces, Endomyces, and 

 Cryptococcus. 



Saccharomyces. These reproduce by budding, have ascopores and no mycelial- 

 like threads. 



S. cerevisiae. This is the ordinary yeast fungus. Used at times as an antiseptic. 

 S. anginae. Found in a case of angina. 



