THE ASPERGILLI 239 



numerous hyphae are given off. Erect filaments, or aerial kyphce, also 

 extend upwards, shaped like a broom, and bearing at the end of their 

 branches the spores. (See Photomicrograph, Fig. 90.) 



Vitality of the Spores. The spores will germinate at any 

 temperature between 2 and 43 C. 22 to 26 C. is the most favourable, 

 while according to Pasteur dry spores withstand a temperature of 108 

 C., but are soon killed when immersed in boiling water. 



Biological Characters. It grows best at room temperature on 

 any of the ordinary media. It is also able to propagate itself sexually 

 when placed under certain conditions, especially the absence of oxygen. 



It is non-pathogenic. 



The green mould growing in the cracks of Roquefort cheese is due to 

 this fungus, which consumes the acid produced by the lactic acid 

 bacteria, thus retarding the development of albumin - degrading 

 organisms. 



Experience having shown the favourable action of this fungus, it is 

 grown on bread, which is dried, powdered, and mixed between the 

 separate layers of the sliced curd. In Edam cheese an organism known 

 as the Streptococcus Hollandicus is mixed with the milk before it is 

 made into cheese. 



THE ASPERGILLI. 



From the mycelium individual threads pass upwards (air-hyphce), and 

 swelling, form clubs without dividing. This swelling of the conidia or 

 fruit-bearers is surrounded by a mass of cylindrical cells, which at their 

 distal ends or extremities produce chains of spherical spores or conidia. 

 Out of each spore a new fungus can develop. When highly nourished, 

 another method of fructification takes place. Some of the terminal 

 branches of the mycelium become twisted like a spiral, and are known as 

 the ( Carpogonium ' ; from the same thread branches grow towards the 

 carpogonium, one of which becomes fused with the terminal portion of 

 the carpogonium, known as the ' Ascogonium ' ; while others, the 

 ' Pollinodia/ ramify around the carpogonium like a capsule, the whole 

 organ being called a perithecium. The ascogonium divides rapidly into 

 a number of oval tubes, inside of which, by endogenous division, small, 

 round, eight-spored asci develop. The aspergilli grows best on bread 

 paste and acid media, beer- wort gelatine, agar, and potatoes. 



Asp. Nidulans. Found on bread ; light green tufts. Air-hyphae 

 present, especially in old cultures which are sometimes coloured light 

 red. Branched sterigmen ; optimumt emperature, 40 C. On potatoes 

 and bread it forms a reddish-brown pigment, which penetrates the 

 medium. The pathogenic properties are the same as the A. fumigatus. 



