476 MUSGKAVE, CLEGG, AND POLK. 



There was not much variation between the different cultures except in the color 

 of the pigment and the appearances wliich have already been described. Potato 

 proved itself to be a very unsatisfactory medium for Wright's organism. Most 

 of his strains grow on it very poorly, and some of them not at all. 



Litmus-milk is not a favorable medium for the differentiation of species. 

 Growth takes place slowly, and with two strains the color is slowly discharged. 

 No other appreciable changes occur in the medium excepting with cultures of, 

 ; 'ehalcea," in which a slightly acid reaction is produced. 



The favorable influence of sugar and glycerine upon cultures of all strains 

 of the group of organisms has been noted repeatedly. Sugar or glycerine 

 containing media not only are the best in securing growth, but with all our 

 species pigment production is more active in these media. 



Pathogenic characters. — The pathogenic character of many varieties of this 

 group of organisms in the human and animal economy is well established. 

 However, experimental inoculations in animals have not given constant results 

 in the hands of other investigators, and our experiments have been uncertain 

 with all animals except monkeys. The details have already been described and 

 it only remains to state here that lesions similar in their gross and histologic 

 appearances to the original ones produced by these organisms, have resulted 

 with each of the strains which we have studied, except with one of the strains 

 of S. Madurae which has already been mentioned in this discussion. 



CONCLUSIONS. 



There is, in human pathology, a very important group of branching, 

 filamentous microorganisms which logically belong to a single genus. 

 The generic name is variously given as Streptotlirix, Actinomyces or 

 Nocardia; the last of these names is probably scientifically the most 

 correct, but because of the present botanical confusion and uncertainty 

 the first is here employed, because of its more general acceptance. 



The following species to judge from our work and from a study of 

 the literature are the most important and may be recognized as estab- 

 lished. There are probably a number of others but the description of 

 many of them are too imperfect to allow of their recognition. 



S. actinomyces Bostroem, 1890. 



S. actinomyces Wolff & Israel, 1891 and Wright, 1905. 



S. nocardii. 



S. eppingeri. 



S. madurce Vincent. 



.?. caprcc Silberschmidt. 



The disease caused by infection with these parasites is properly named 

 streptothricosis, with actinomycosis and nocardiosis as synonyms. Other 

 names, such as lumpy-jaw, madura foot, mycetoma, etc., should be 

 considered more as describing anatomic location rather than as designa- 

 tions relating to any special or specific cause of infection. Mycetoma 

 might well be taken as the correct name for the group of infections if 

 a strict interpretation of rules of nomenclature is followed, but usage 

 renders it perhaj)S more desirable to retain the name as representing 



