44 Structure and Classification of Micro-organisms 



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 

 Paltauft 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 

 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 



Fig. 13. — Mucor mucedo. Single-celled mycelium with three hyphae and one 

 developed sporangium (After Kny, from Tavel). 



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 hyphse, 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 

 form of reproduction also takes place through the production of 

 ascospores. Many species are known, only a few of which are 

 pathogenic. 



Aspergillus malignum has been found by von Lindt in the auditory 

 meatus of man. 



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

 t Huckel-Losch in Flugge, "Die Mikroorganismen." J Ibid. 



