SOFT CHEESE MANUFACTURE 35 



excessive humidity the white mould changes to 

 black, a variety known as the Aspergillus niger, 

 while the blue mould, which is responsible for 

 so much work in the process of ripening, is the 

 common Penicillium glaucmn the shape of the 

 tiny filaments known as hyphae, which are re- 

 sponsible for the propagation of the spores of the 

 mould, resembling a painter's brush, hence the 

 Latin word penidllium. It is curious that these 

 tiny fungoid plants should have so important 

 an influence in the ripening of cheese. The 

 blue mould is unquestionably the dominant 

 fungus in the atmosphere of the dairy ; it will 

 not only grow luxuriantly at the temperature 

 at which soft cheese ripens, but at a still lower 

 temperature when it is provided with a suitable 

 soil or feeding material. It has been assumed 

 by some writers that it is essential to cultivate 

 the moulds common to cheese ; but this is not 

 the case. It is common to every household, 

 and its spores or seeds are so easily dispersed 

 by the movement of the atmosphere that 

 wherever such a material as cheese is placed 

 it is certain to be attacked. The maker 

 of soft cheese should, therefore, observe the 



