MOULDS 



243 



FILM FORMATION. 



MOULDS. 



The moulds, mycelial fungi, or hypomycetes, as they are 

 called, are frequently seen upon the surface of articles of 

 food, fruit, etc., after keeping for some time in a damp 

 place. They are, for the most part, harmless saprophytes, 

 but several of them are of pathological interest, as being 

 associated with, or the cause of, various morbid processes. 

 In some instances this is seen only in animals. This cir- 

 cumstance does not strictly show that such moulds are 

 pathogenic for man ; but it is certainly difficult to establish 

 strictly that they are not pathogenic, and as the conditions 

 of moisture, etc., which usually favour their growth are 

 insanitary, their presence should be taken to indicate in- 

 sanitary conditions. The moulds form spores, and, like 

 the bacteria proper, are remarkable for the great resistance 

 they offer to external influences, and which under favour- 

 able conditions, such as moisture, warmth, and nourish- 

 ment, develop into complete individuals. 



The spores, or conidia, as they are called, shoot off little 

 buds, which lengthen at the end by fission, giving rise to 

 a long thread of cylindrical cells, which sometimes branch, 

 forming a freely-growing network of fibres known as mycelia. 



The heads of these mycelia then form spherical or oval 

 cells, which are the seed-bearing organs known as the 



