MOLDS AND YEASTS AND DISEASES CAUSED BY THEM 



233 



The mold has been found growing as a parasite in the auditory 

 canal. 



More than a hundred species of Mucor have been described 

 and several of them cause disease and death when injected into 

 animals. 



Aspergillus Glaucus. This is very widely distributed in 

 nature, occurring on fruits, moist bread and other food substances 

 and very frequently as a con- 

 tamination in laboratory cul- 

 tures. The aerial spore-bear- 

 ing hypha (conidiophore) is 

 erect, about i mm. long, swollen 

 at the end to a diameter of 20 

 to 40;*. On the surface of this 

 spherical head are numerous 

 closely packed spore-bearing 

 sterigmae, each of which bears 

 at its tip a chain of spherical 

 spores (conidia) which are 

 budded off from it. The coni- 

 dia are gray to olive green in 

 color. Ascospores are also produced, grouped together as yellow 

 masses, called perithecia, on the surface of the medium. The 

 mold is not pathogenic. Probably a considerable number of 

 different species have been included under this name. 



Aspergillus Fumigatus. The growth of this mold is at first 

 bluish and later grayish-green. It is widely distributed. The 

 sterigmae are unbranched, thickly set on the swollen end of the 

 spore-bearing hypha. The conidia measure 2.5 to 3^. The for- 

 mation of ascospores has also been observed. Aspergillus fumi- 

 gatus plays a part in the heating of hay and sprouting barley, 

 and is the most common of the pathogenic aspergilli. It infects 

 doves and other birds naturally, sometimes causing veritable 

 epidemics, and the disease has been observed in bird fanciers, 

 in whom it runs a clinical course very similar to that of pulmonary 



FIG. 91. Aspergillus fumigatus from the 

 lung of a parrot. (After PlauL} 



