TAXONOMY 185 



Animal Inoculations. Laboratory animals are somewhat resistant 

 to infection so that animal inoculation is not a useful method of lab- 

 oratory diagnosis. However, when large numbers of spores from a 

 culture are injected typical lesions result, and this is a useful method 

 of confirming the identify of a culture. Spring" found that mice 

 are the most susceptible of the common laboratory animals, guinea 

 pigs being more resistant, and rabbits practically immune. When 

 the animals are inoculated intraperitoneally, small caseous nodules 

 develop on the peritoneal surfaces which contain the budding fungus 

 cells. These are more numerous in mice than in other animals. The 

 type of tissue reaction in experimentally inoculated animals varies 

 with the virulence of the strain and the resistance of the animal, from 

 frank abscesses to lesions like tubercles, including giant cells. Ben- 

 ham 3 stated that dogs and monkeys are most susceptible. DeMon- 

 breun ^ produced in monkeys cutaneous blastomycosis of the type 

 seen in man. Baker ^ discussed experimental blastomycosis in mice. 

 Spontaneous blastomycosis in dogs has been reported. 



Taxonomy. Both the name of the disease and that of its etiolog- 

 ical agent are. misnomers. Blastomycosis is used in Europe to desig- 

 nate any disease caused by a budding yeast-like fungus. Whether or 

 not this terminology is justified, it has been the source of consider- 

 able confusion. Although Blastomyces dermatitidis produces buds 

 of a sort in its parasitic growth phase, it is unlike the yeasts both 

 in tissue and in culture, as already pointed out. 



B. dermatitidis, likewise, is an incorrect name for the fungus be- 

 cause that generic name properly belongs to an unrelated group of 

 fungi. Nevertheless, both names are generally recognized, and be- 

 cause of their familiarity we continue to use them here. 



Misinterpretation of oil droplets and stored food particles within 

 chlamydospores and other structures have led some observers to place 

 B. dermatitidis among the Ascomycetes. It is properly classified 

 among the Fungi Imperfecta Although its relationships are not 

 known, its resemblance in culture to Histoplasma capsulatum should 

 be pointed out. Skin tests indicate an immunological cross reaction 

 between these two fungi. 



Several species names have been proposed for the fungus causing 

 blastomycosis. A critical examination of the strains named shows 

 that some of them are varieties of B. dermatitidis characterized by 

 minor differences which do not deserve specific differentiation. It is 

 evident that in other cases the multiplication of names has been due 

 to failure to differentiate B. dermatitidis from Coccidioides or other 

 fungi. 



