ACTINOMYCES BOVIS 313 



relationship to baldness. Some workers have maintained that this 

 organism is the cause of dandruff and seborrheic dermatitis; 

 others, that it is a harmless saprophyte. Unna, one of the foremost 

 students of this problem, is among those who believe that P. ovale, 

 which he called the "bottle bacillus" because of the shape of the 

 cells, is the etiologic agent in this scaly condition of the scalp; 

 he designated the disease "pityriasis capitis." 



Among the recent workers who regard this organism as patho- 

 genic is xMoore (1935), Ota and Huang (1933), on the other hand, 

 concluded that their yeast-like isolates from seborrheic dermatitis, 

 belonging to Pityrosporum, were saprophytes. The most critical 

 study of this whole problem is that of MacKee and his associates 

 (1938). They made direct examination of the scrapings of 

 normal and diseased scalps and in one series found P. ovale in 86 

 of the 100 cases examined, prevalence being little different on the 

 normal and on the diseased scalps. From these scrapings they also 

 cultured species of molds belonging to Aspergillus, Rhizopus, Al- 

 ternaria, Chaetomium, Torula, Dematium, and Mycoderma, and 

 in addition several species of Staphylococcus. MacKee and his 

 associates conclude: 'The occurrence at times of the organism 

 [P. ovale] on all types of scalps and the fact that it may occa- 

 sionally be found in as large numbers on the normal scalp as on one 

 with severe dandruff leads one to consider the possibility that this 

 yeast is a saprophyte, and grows well in the presence of scaling 

 or in sebaceous material but is not responsible for the presence 

 of these findings." 



D 



ACTINOMYCES BOVIS 



Bacteriologists and mycologists are not in accord on the sys- 

 tematic position of Actinomyces, bacteriologists regarding it as 

 among the Schizomvcetes, and mycologists including it among 

 the Hvphomycetes. Actinomyces is a large genus and includes 

 not only many species that are pathogenic to man and other ani- 

 mals, but also a few plant pathogens and many species that are 

 normal inhabitants of the soil. 



The mycelium of Actinomyces consists of very slender, 

 branched hyphae, commonly about 1 [x in diameter. More or less 

 specialized branches become sporogenous and by segmentation 



