972 THE HIGHER BACTERIA, MOLDS AND FUNGI 



with black, white, yellow, or red granules. These different varieties 

 of the disease though clinically similar may apparently be produced 

 by a large number of diffeernt parasites all belonging to the fungi 

 or higher bacteria. We will mention below the few cases from 

 which aspergilli and allied molds have been isolated. In the ma- 

 jority of cases, organisms similar to the nocardia have been found. 

 Brurnpt divides them into two genera: the madurella having septate 

 mycelia and the discomyces which is without septa, but this distinc- 

 tion is not generally recognized. For a discussion of the character- 

 istics of the various strains one should refer to the works of Brumpt 

 and of Castellani. 



The parasite of the commoner black variety which certainly seems 

 to be a distinct disease has been carefully studied by Wright from 

 whose description the following points are taken. 



The small, brittle granules observed under the microscope show 

 a dark, almost opaque center along the edges of which, filaments, 

 or hyphse, may be seen in a thickly matted mass. By crushing the 

 granules under a cover-slip in a drop of sodium hypochlorite or of 

 strong sodium hydrate, the black amorphous pigment is dissolved 

 and the structural elements of the fungus may be observed. They 

 seem to be composed of a dense meshwork of mycelial threads which 

 are thick and often swollen, and show many branches. Transverse 

 partitions are placed at short distances and the individual filaments 

 may be very long. Spores were not observed by Wright. In a 

 series of over fifty cultivations on artificial media from the original 

 lesion, Wright obtained growth in a large percentage. 



In broth, he obtained at first a rapid growth of long hyphae which 

 eventually formed a structure which he compares in appearance to 

 a powder-puff. 



On agar, growth appeared within less than a week and spread over 

 the surface of the medium as a thick meshwork of spreading hyphae 

 of a grayish color. In old cultures black granules appeared among 

 the mycelial meshes. 



On potato, he observed a dense velvety membrane, centrally of a 

 pale brown, white at the periphery. Small brown droplets appeared 

 on the growth in old cultures. 



Animal inoculation with this microorganism has so far been un- 

 successful. 



