382 ACTINOMYCOSIS 



pronounced fragmentation of the mycelium, and in forming a pellicle 

 of rosy color on milk. It is pathogenic for both rabbits and guinea 

 pigs. 



Several strains have been isolated from spontaneous infections in 

 dogs which have been designated N. Cards, though none has been ade- 

 quately described. One studied by Musgrave and Clegg appeared 

 to be identical with N. Caprae. 



One of the varieties which have been found in man, A^. asteroides, 

 is the best known. This species was discovered by Eppinger and 

 named by him Cladothrix asteroides. The same organism has been 

 found in a number of other cases since. On solid media it forms a 

 wrinkled growth of mealy consistency varying from pale yellow to 

 deep orange in color, depending upon the age of the culture and the 

 composition of the medium. Aerial mycelium is rarely formed ; when 

 present it is white and very scant. Most strains readily dissociate 

 into one producing a short white aerial mycelium and one forming a 

 waxy, wrinkled growth closely resembling that of the tubercle ba- 

 cillus. It does not liquefy gelatin or peptonize milk. The organism 

 is very pathogenic to guinea pigs and rabbits, although some strains 

 show reduced virulence. 



An acidfast strain isolated from a human case by Ayoyama and 

 Myamoto resembled A^. Caprae in color. Another one isolated by 

 Birt and Leishman gave a snow-white growth and peptonized milk. 

 A fourth type obtained by Berestneff liquefied gelatin and was not 

 pathogenic for laboratory animals. 



Henrici and Gardner ^^ isolated an acidfast actinomycete from a 

 human case which resembled N. asteroides in forming a buff-colored 

 mycelium, but with a very pronounced production of aerial mycelium, 

 so that the growth was of a pronounced chalky white; and which 

 differed from the other acidfast strains in being actively proteolytic, 

 liquefying gelatin, producing in milk first a rennin coagulation and 

 then peptonization, and giving a pronounced dark brown tyrosinase 

 reaction. But as mentioned in a preceding chapter, these characters 

 have not remained constant, save the white aerial mycelium and the 

 darkening of protein-containing media. They named their organism 

 Actinomyces gypsoides. It was very pathogenic for rabbits and 

 guinea pigs. 



In 1920 Henrici and Gardner were able to collect from the literature 

 records of twenty-six cases in man. In all but three of these the 

 infection was primary in the lungs or peribronchial lymph nodes. 

 In the lungs there is produced a caseous bronchopneumonia with 

 eventually softening and cavitation, but there is a pronounced tend- 



