THE PATHOGENIC HIGHER BACTERIA 535 



monic course of one or two weeks' duration. A chronic case may 

 abruptly become generalized and terminate fatally. It is not defi- 

 nitely known if all chronic cases prove fatal or if some eventually 

 recover. The Nocardia appear to be widely distributed in the soil, 

 water, upon foodstuffs and upon plants and it is suggestive that 

 nearly 50 per cent, of all cases reported have been infections of the 

 head and neck. 1 About 20 per cent, of cases are chest infections and 

 the clinical symptoms are very like those of tuberculosis. If repeated 

 sputum examinations are negative although the syndrome suggests 

 tuberculosis, search should be made for Nocardia. 



Morphology. The Nocardia are very pleiomorphic; in purulent 

 material and other discharges the organisms are of varying length, 

 some short and rod shaped, others long-branched filaments (mycelia). 

 The filaments usually segment or fragment, producing the shorter 

 bacillary forms and, in artificial media, forming chains of spores as 

 well. Old cultures in artificial media are composed chiefly of bacilloid 

 forms long, somewhat curved filaments which may or may not be 

 branched, and spores which occur singly or in small groups and pairs. 

 The organisms may or may not be acid-fast, but they are Gram- 

 positive. The granules or u drusen" so characteristic of actinomycotic 

 infections are not found in Nocardial mycoses. 



Cultivation. Nocardia may frequently be grown upon artificial 

 media gelatin or agar directly from pus or other morbid material. 

 The colonies develop slowly and after five to seven days they appear 

 as gray, opaque, shining plaques which may reach 3 to 5 mm. in 

 diameter after prolonged incubation. A densely matted pellicle 

 composed of branched and unbranched filaments forms upon the 

 surface of broth and a flocculent sediment gradually collects at the 

 bottom of the tube. Loffler's blood serum appears to be the most 

 favorable medium for the initial growth of Nocardia directly from the 

 tissues. 



The inoculation of cultures into rabbits or guinea-pigs frequently 

 leads to chronic abscesses, bronchopneumonia or a rapidly fatal 

 generalized infection, depending upon the virulence of the organism 

 and the site of inoculation. Recently Claypole 2 has prepared a series 

 of "Streptotrichins;" glycerin bouillon cultures made from non-acid- 

 fast mycelial organisms and the partly acid-fast bacillary forms of 

 Nocardia, which give definite skin reactions on persons with nocardial 



1 Claypole, Jour. Am. Med. Assn., 1914, xiii, 604. 



2 Jour. Am. Med. Assn., 1914, Ixiii, 603. 



