MOULDS 173 



It penetrates into the deep layers of the skin and sets up 

 abscesses of slow development and spread. These may 

 break down and leave a sluggish ulcer which later shows a 

 tendency to heal. More serious phases of this infection are, 

 however, met when the lung is first affected. Then a pneu- 

 monia, ending in sepsis, results. In these cases the outlook 

 is hopeless. The disease is probably due wholly to the 

 mechanical presence of the yeasts. The germs leave the 

 body in pus or sputum. They are not easily destroyed, and 

 all infective matter should be burned. It is, however, not a 

 very contagious disease. 



There is no antiserum treatment, and the few cases upon 

 which vaccines were tried have not held out much promise 

 in this direction. Yeasts are held responsible for some 

 diseases in lower animals, but the question is not yet settled . 

 When injected into them intentionally varying results are 

 obtained. It can be said that they settle by preference in 

 the lungs and spleen. 



MOULDS. 



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

 following remarks pertain to those forms having some impor- 

 tance 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 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. 



Multiplication occurs in two ways. Upon the hyphse 

 may develop a reproductive organ, the sporangium, con- 



