THE MUCORS 241 



THE MUCORS. 



Specially characterised by aseptate hyphae springing from the 

 mycelium. In these hyphae a large sporangium develops apically and 

 by fission. Inside it spores are produced, which later are liberated by 

 the bursting of the sporangium. Under some conditions proliferation 

 occurs by conjugation of two bodies forming what is called the zygo- 

 spores. 



Mucor Corymbifer. Occurs as greyish tufts. The hyphae come 

 off from the mycelium at an angle, and are branched with colourless 

 sporangia. The spores are small, 3 /* to 2 /A. Optimum temperature, 

 37 C. 



Pathogenesis. When injected into the veins of rabbits, death follows 

 in from two to three days. The clumps of fungus are mostly found in 

 the kidneys and lymph-follicles of the intestinal mucosa. Dogs are 

 immune. (For Photomicrograph of this fungus, see Fig. 93.) 



Mucor Mucedo. Found on horse manure as a whitish growth, like 

 thistledown. The hyphae are 1 to 13 cms. in length, and may be single 

 or branched ; crystals of oxalate of lime occur on the outside of the spor- 

 angia, which later are coloured brown or black. (See Photomicrograph, 

 Fig. 94.) Optimum temperature, 37 C. ; non-pathogenic. 



Mucor Pusillus. Found in moist bread, and occurs in tufts, which 

 are at first white and get grey. The mycelium is unusually fine. The 

 sporangia are covered with a spinous membrane ; optimum temperature, 

 45 C. 



Pathogenesis. Same as Mucor corymbifer. 



Mucor Ramosus. Occurs on moist bread as tufts, at first white, 

 and later brownish. The mycelium is very much branched, and has long 

 branched air hyphae and large spores. Optimum temperature, 40 C. 



Pathogenesis. Same as Mucor corymbifer. 



Mucor Racemosus. Found on sugar and starchy substances. 

 Has many delicate fruit hyphae not exceeding 1 to 5 cms. in length. 

 Sporangia are yellow or yellowish-brown, with round spores. 



Mucor Stolonifer. The mycelium has branches which at first 

 ascend and then descend, and are covered with fine root hairs. 



The sporangia are deep black and tuberculated with brown globose 

 spores, 10 to 20 /A in diameter. The zygospores are blackish-brown. 



Mucor Rhizopodiformis. The mycelium is at first quite white, and 

 later turns greyish. The hyphae are twisted, at first ascend, and then 

 grow down again into the medium, where they get covered with root 

 hairs. Spores colourless ; diameter 5 to 6 fi, 



Q 



