PART HI 

 SPECIFIC MICRO-ORGANISMS 



CHAPTER XIV 



THE MOLDS AND YEASTS AND DISEASES CAUSED BY 



THEM 



Mucor Mucedo.- — This is the most common species of mucof , 

 especially about barns and on manure. It produces a network 

 of threads (mycelium) in the substratum, arid zygospores are pro- 

 duced here by the union of two cells. The aerial hyphse are 

 vertical, about lo cm. in length and bear a spherical spore sac 

 (sporangium) at the end. The sporangium is at first yellow, 

 later brown and finally black and covered with crystals. The 

 contained spores are 4 to 6m wide by 7 to lo/i long. It is sapro- 

 phytic and may be found as a contamination on culture media. 



Mucor Corymbifer. — ^Lichtheim found this mold growing on 

 a bread-infusion gelatin ^as an accidental contamination. The 

 growth is at first white and later gray. The spore-bearing hyphae 

 are long and irregularly branched, and each branch bears a pear- 

 shaped sporangium ip to 70/1 in diameter. The contained spores 

 are small (2X3^)- Intravenous injection of the spores into rab- 

 bits causes severe nephritis and death in two or three days. 

 The mold has been found growing as a parasite in the auditory 

 canal. 



More than a hundred species of Mucor have been described 

 and several of them cause disease and death when injected into 



animals. 



237 



