COHNISTREPTOTHRIX FOERSTERI 



1067 



. The fungus is easily cultivated, aerobically and anaerobically. 

 |i' On maltose agar it produces small white colonies; on broth it 

 develops only at the bottom of the tube. 



Cohnistreptothrix foersteri Cohn, 1874. 



Synonyms,— Streptothrix foersteri Cohn, 1874; Odspora foersteri 

 Radais et Sauvageau, 1892; Discomyces foersteri Blanchard, 1895; 

 Cohnistreptothrix foersteri Pinoy, 1911. 



Mycelial threads very slender, seldom ramified, often terminating 

 in a chain of rod-like or coccus-like elements. Masses of the fungus 

 form some peculiar white bodies or concretions (Desmarres' dacryo- 

 lithes), about 2 millimetres in diameter, which are occasionally 

 found in the lachrymal canals of man. 



The fungus has been cultivated with difficulty aerobically and 

 anaerobically by several authors, among whom Kastalky, Axenfeld, 

 Morax, and Landrieu. The last named has made a thorough in- 

 vestigation of the fungus, which, according to him, shows a slow 

 growth and gives rise on maltose agar to small cerebriform colonies 

 of a grey-stone colour. 



The peculiar concretions found in the lachrymal canals were first studied 

 by Cesoin in 1670 and Sandifors in 1779. Desmarres, in 1842. considered 

 them to be calculi composed of lime salts, and indicated them by the name 

 of dacryolithes. Gruby believed they were induced by the fungus of Favus, 

 but his observations remained unpublished. A. de Graefe, in 1854, first 

 stated in a published work that these concretions were of mycotic origin. 

 He thought they were due to A chorion schoenleini, while Conheim and others 

 believed them to be caused by Nocardia [Stveptothrix) buccalis. In 1875 

 Cohn described the fungus under the name of Stveptothrix foersteri. 



Cohnistreptothrix tenuis (Castellani, 1911). 



Synonym. — Nocardia tenuis Castellani, 1910. 



Found by Castellani in a nodular affection of the hair of the 

 axillary regions. In the parasitic stage, the germ appears in the 

 shape of bacillary-like bodies, varying in breadth (0-2 to o-6 ^) and 

 in length (2 to 10 (jl), packed together and embedded into an 

 amorphous cementing substance. The bacillary bodies are either 

 straight or bent, seldom branching. Gram-positive, but not acid- 

 fast. Masses of this fungus embedded in amorphous cementing 

 substance form the nodules of trichomycosis fiava of the axillary 

 regions. (See Plate VI., p. 1034). 



In the black variety of the affection Nocardia tenuis is associated with a 

 black pigment-producing coccus — -Nigrococcus nigrescens Castellani, 191 1. In 

 the red variety the same Nocardia is associated with a red pigment-producing 

 coccus found by Castellani, and called by Chalmers and O'Farrell Rhodococcus 

 castellanii Chalmers 3.n6. O'Farrell, 191 3. 



For the growth of the black pigment-producing coccus, sugar media are 

 more suitable than ordinary agar. On Sabouraud's agar the colonies of this 

 coccus appear twenty-four to forty-eight hours after inoculation. They are 

 roundish, at first white, but after a couple of days the centre of each colony 

 turns black; at this pigmentation slowly spreads excentrically. After a 

 time the colonies coalesce into a jet-black mass. On glucose agar the coccus 

 presents the same characters. On ordinary agar the pigmentation is much less 

 marked or almost absent. 



