42 Structure and Classification of Micro-organisms 



Mucors are not infrequent organisms of the atmosphere and 

 occasionally appear as contaminations upon solid culture-media. 

 About 130 species are known. Of these, Mucor corymbifer, Mucor 

 rhizopodiformis, Mucor ramosus, Mucor pusillus, Mucor septatus, 

 and Mucor conoides are said by Plant* to be pathogenic when 

 introduced into laboratory animals. Mucor corymbifer has been 

 known to produce inflammation of the external auditory meatus in 

 man.f General mucor mycosis in man has also been observed by 

 PaltaufJ to result from the presence of the same organism. 



4. Aspergillus and Eurotium. — The organisms of this genus are 

 included among the Ascomycetes. They are common organisms of 



Fig. 12. — Mucor mucedo. DifEerent stages in the formation and germination 

 of the zygospore: i, Two conjugating branches in contact; 2, septation of the 

 conjugating cells (o) from the suspensors (6); 3, more advanced stage in the 

 development of the conjugating cells (a); 4, ripe zygospore (J) between^ the 

 suspensors {a); 5, germinating zygospore with a germ-tube bearing a sporangium. 

 (After Brefeld.) 



the air and frequent contaminations of solid culture-media. 

 To secure them an agar-agar plate can be exposed to the atmosphere 

 of the laboratory for a short time, then covered and stood aside for a 

 day or two, when tangled mycelial growths with rapidly spreading 

 hyphae will usually be discovered. The recognition is easily made 

 when the sporangia appear. These are well shown in the accom- 

 panying illustration. The mycelium is divided into many cells. 

 Reproduction is asexual and takes place through conidia spores. 

 The fruit hyphs, which are aerial, terminate in rounded extremities 

 which are known as columella, from which many radiating sterig- 

 mata arise, each terminating in a series of rounded spores. A sexual 



* Kolle and Wassermann, "Die Pathogenen Mikroorganismen," 1903, i, 552. 

 t Hiickel-Losch in Flugge, "Die Mikroorganismen." {Ibid. 



