202 INFECTIONS CAUSED BY MOLDS 



of mycetomas. These clusters of fungus cells may be in giant cells 

 or smTounded by polymorphonuclear leucocytes. 



Appearance of Fungus in Culture. Examination of sections of 

 the lesion does not indicate that more than a single species of fungus 

 is involved in the etiology of chromoblastomycosis. However, when 

 cultures are made, one of three fungi may be isolated. One is 

 Phialophora verrucosa, first isolated in Boston from the first re- 

 ported case,^' ^° and since isolated from other North American and 



Fig. 102. Culture of Phialophora Pedrosoi. 



from South American cases; one is P. Pedrosoi,^^ first isolated in 

 Brazil and since isolated from cases in many parts of the world; and 

 one is P. compactufn isolated in Puerto Rico by Carrion.^ The sec- 

 ond species is the most commonly found. 



There are some strains of both P. verrucosa and P. Pedrosoi whose 

 individual differences are manifested by colony characteristics but 

 in general these two species are indistinguishable in colony appear- 

 ance. Microscopic examination shows a difference in method of 

 sporulation, but careful study shows that even here there is an evi- 

 dent relationship and the differences are quantitative and not qualita- 

 tive. This point will be discussed further in the paragraph on tax- 

 onomy. 



P. verrucosa produces short lateral or terminal conidiophores which 

 may be of nearly uniform diameter or may be enlarged midway to 

 form a bottle-shaped or vase-shaped cell (Fig. 103). This conidio- 



