PART III. 

 SPECIFIC MICRO-ORGANISMS 



CHAPTER XIV. 



THE MOLDS AND YEASTS AND DISEASES CAUSED 



BY THEM. 



The general characters of molds and yeasts have been men- 

 tioned in a previous chapter. The generic and specific relation- 

 ships of many of those commonly met with by the pathological 

 bacteriologist are in a state of confusion. No claim of systematic 

 arrangement is made for the material here presented. 



Mucor Mucedo. This is the most common species of mucor, 

 especially about barns and on manure. It produces a network 

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

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

 vertical, about 10 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 6^ wide by 7 to ID/* long. It is 

 saprophytic. 



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 10 to yo/* 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. 



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