HIGHER BACTERIA 367 



mode of life. The group is characterized by a filamentous 

 growth. The filaments are terminated by hyphae. The fila- 

 ments growing together, more or less interlacing, form the 

 mycelium. In this group belong the moles, and in their culti- 

 vation they prefer an acid to an alkaline medium. 



Comparatively few of the members of this class are 

 capable of growing in living animal tissues. Plaut 19 has di- 

 vided the fungi pathogenic for man into three groups accord- 

 ing to their pathogenic effects: 1, the moles in their narrowest 

 sense (mucor and aspergillus) ; 2, fungus of thrush ; and.3, the 

 fungi attacking the skin. The disease in the mouth of chil- 

 dren known as thrush is due to Oidium albicans. Favus, a 

 disease attacking the hairy portions of man and animals, is due 

 to Achorion Schoenleinii. Ringworm, a disease of the skin and 

 hair, occurring most often in children, but also in animals, is 

 caused by members of this family. 



GENUS ASPERGILLUS. 



The members of this genus are widely distributed and 

 there are a number of species, several hundred having been 

 described. Of these only two or three seem to be important in 

 the production of animal diseases and of these fumigatus is the 

 most important. It has been found to cause lesions in birds 

 and it has also been found associated with morbid tissues in 

 other animals. It grows readily on culture media. It pro- 

 duces conidiophores, the enlarged tip of which is hemispheri- 

 cal and varies from 8 to 20 /x in diameter. It is readily isolated 

 from the lesions in which it occurs by cultivation on artificial 

 media. It is an aerobe and according to Mohler and Buckley it 

 grows best at a temperature of from 35 to 40 C. Spores are 

 not formed below 20 C. 



Pearson and Ravenel 20 have described an interesting case 

 of pneumonomycosis in a cow due to Aspergillus fumigatus. 

 In their case the aspergillus showed fruit hyphae and spores 



10 Plaut. Kolle and Wassermann's Handbuch, Bd. I, p. 549. 

 *' Pearson and Ravenel. The University Medical Magazine, Aug. 

 1911. 



