168 A IDS TO BACTERIOLOGY 



mass (sclerotium). Lower members of the group have 

 both asexual and sexual methods of reproduction, while 

 among the high fungi sexual development is less evident. 

 According to the form of the seed-bearing organ, the 

 moulds are divided into: 



1. Mucor inse. The end of an aerial hypha swells into 

 a knob, known as a columella, around which a spherical 

 seed-capsule or sporangium forms. When ripe, the spores 

 burst the enclosing membrane, and thus become free. 



2. Aspergillinse (Knob -Moulds). The heads of aerial 

 hyphae are studded with spore-carriers, or sterigmata. 

 Each sterigma bears a chain of spores (gonidia). 



3. Pemcilliacese. Aerial hyphse (goniodophores) branch 

 at the apex forming basidia, on the terminals of which 

 are the sterigmata, from which the conidia, or spores, 

 are separated in the form of chains. 



The most important members of these groups are the 

 undermentioned : 



Mucor mucedo. A mould frequently seen on food- 

 stuffs, particularly stale moist bread, and on animal 

 excreta. It grows well on an acid medium, forming a 

 white fur. It is not pathogenic. 



Mucor rhizopodiformis forms a similar growth to the 

 above. A culture on bread has an aromatic odour. 



Mucor corymbifer forms a dense white fur on bread, 

 resembling cotton-wool. 



Mucor ramosus grows on bread and potato as a white 

 fur, which soon changes to greyish -brown. 



These last three mucors are pathogenic. Intravenous 

 injection of their spores causes fatal disease in rabbits. 



Aspergillus niger, A. albus, and A. glaucus grow upon 

 bread, candied fruit, etc. The last two organisms grow 

 best at blood-heat, when they soon overgrow the nutrient 

 medium. 



Aspergillus flavescens and A. fumigatus. The former 

 is distinguished by its well-marked fructifications and the 

 greenish colour of its culture, the latter by its fine fructifi- 

 cations and ash-grey fur. On gelatin plates the filaments 

 grow rapidly into the medium, causing liquefaction. 

 Both organisms grow at blood-heat. Both are pathogenic, 

 growing in various parts of the body particularly the 

 ear, producing otomycosis. They have been also found 

 growing in the lungs and on the nasal mucous membrane. 



