514 THE ASPERGILLI 



of the later stages of decomposition. They are green to gray-green forms which 

 produce brilliant yellow, orange, red, and purple-red colors in the substratum. Many 

 races of this group have been reported from soil, from old cheese, from dried salt 

 meats, and from miscellaneous cultures. The range of colors and structures encoun- 

 tered was reported by Thom and Church, but very little of their significance in nature 

 has been determined. 



Closely allied to the A. versicolor series, A. sydmvi is also widely distributed, 

 producing delicate stalks, globose blue-green heads, and usually brilliant orange-to- 

 red colors in the substratum. In flask experiments Kopeloff found it exceedingly 

 active in inverting sucrose. Aside from this work very little is known of its activities. 

 Another aggregate of green species, A. nidulans Eidam, is represented by numerous 

 Strains constantly encountered in studies of the soil and readily cultivated. In this 

 group certain strains produce perithecia and ascospores which lend themselves readily 

 to culture. As normally encountered the perithecial walls, asci, and ascospores are 

 purple red. They turn blue with the addition of alkali, then red again with acid. 

 They thus furnish a favorable species for studying the relation of an organism to the 

 hydrogen-ion concentration of the substratum. 



Thom and Church described a number of perithecial strains differing somewhat 

 in cultural characters, in the rate of ascospore production, and in the markings of the 

 ascospores themselves. Other cultures have refused to produce perithecia as ordinari- 

 ly handled in the laboratory. A. nidulans in this way furnishes a favorable species 

 for the investigation of the conditions surrounding ascospore production. Colorless 

 ascopores otherwise closely resembling those of A . nidulans are found in A . fischeri 

 Wehmer, which in its conidial form appears to be a close relative of A. fiimigatus. 



The general morphology of head and conidium production found in A. nidulans 

 is reproduced with differences in color in A . terreus Thom, a brown form common in 

 American soils; in A. ustus Bainier, a gray to fuscous-brown form also constantly 

 met in soil studies; and in A.flavipes Bainier, with its white heads and yellow stalks. 

 Aside from the routine studies made by those who have described these forms, their 

 place in nature is comparatively unknown. 



Certain species are used for particular purposes. A. wentii, a brown form, is used 

 in making a bean preparation in Java. An enzyme preparation from A . okazakii has 

 been patented in Japan. Such enzyme preparations are used in the United States 

 to clarify jellies and in the manufacture of pectin preparations used in jelly-making. 

 Great possibilities of extension in the utilization of mold enzymes are indicated by 

 the progress already made. Thus far very few species have been studied biochemical- 

 ly, and even these show possibilities as yet undeveloped. 



PATHOGEMICITY OF ASPERGILLI 



Although the Aspergilli are primarily saprophytes whose function consists in the 

 destruction of organic remains, especially carbohydrates, some of these species are 

 found capable of parasitic habits. These infections of man and other animals have 

 been reported from various countries and in many forms, thus indicating that they 

 are widespread causes of pathological conditions. 



The earliest studies of this kind rept)rted various species in ulcerations of the ear. 



