MOULDS 



197 



MOULDS. 



This group is by no means so simple as the yeasts. 

 The following remarks pertain to those forms having 

 some importance in human medicine. The moulds 

 or branching fungi consists of long, interlacing, hair- 

 like threads called mycelia (sing., mycelium}, from 

 which come off end branches called hyphse, upon 



FIG. 55. Penicillium glaucum. Gelatin culture. Spread stained 

 with gentian violet. 500 to 1. (From Itzerott and Niemann.) 



which the reproducing parts usually develop. These 

 mycelia are made up either of one long, continuous 

 cell with a cell wall, and an easily distinguishable, long 

 nucleus, or they may break up into shorter forms each 

 with a separate nucleus. Their length and width are 

 so variable that measurements would be misleading. 

 Their general naked-eye appearance and size is well 

 known to any who have observed the felt-like or cottony 

 moulds upon decaying organic matter. 



