The Yeasts, or Blastomycetes 43 



genie action. For a long time there has been a disposition 

 to regard Bacillus tuberculosis as a form of strep to thrix, since 

 old cultures show branching involution forms. The old 

 genus actinomyces is also included by a number of writers 

 among the streptothrices, so that the Actinomyces bovis of 

 Bollinger is called Strep to thrix actinomyces, the Actinomyces 

 madurae, Streptothrix madurae, and the organism found by 

 Nocard in the disease known as " farcin du bauf," Strepto- 

 thrix farcinica. There seems, however, no adequate ground 

 for this arrangement, and the old genus Actinomyces should 

 be kept. Bppinger, found a streptothrix in the pus of a 

 cerebral abscess, and Petruschky, Berestneff, Flexner, 

 Norris, and Larkin have found streptothrices in cases of 

 pulmonary disease simulating tuberculosis. The organisms 

 described by these writers were not identical, so that there are 

 probably several different species. They usually grow well 

 upon ordinary media and upon solid media form whitish, 

 glistening, well-circumscribed colonies attaining a diameter 

 of several millimeters. As they grow old they turn yellowish 

 or brownish. They liquefy gelatin. Some of the cultures 

 were not harmful to the laboratory animals, others caused 

 suppuration. 



Actinomyces. The chief characterization of the organisms 

 of this group is a clavate expansion of the terminal ends of 

 radiating filaments. These are seen in sections of diseased 

 tissues containing the organisms, but rarely are well shown in 

 the artificial cultures. For further particulars of these or- 

 ganisms see Actinomyces bovis, etc. 



THE YEASTS, OR BLASTOMYCETES. 



The organisms of this group are sharply separated from the 

 bacteria by their larger size, elliptic form, and by multipli- 

 cation by gemmation or budding. 



Each organism is surrounded by a sharply defined, 

 doubly contoured, highly refracting, transparent cellulose 

 envelope. Commonly each cell contains one or more distinct 

 vacuoles. When multiplication is in progress, smaller and 

 larger buds are formed. 



The yeasts, of which Saccharomyces cerevisiae may be 

 taken as the type, are active fermentative organisms, quickly 

 splitting the sugars into CO 2 and alcohol, and are largely cul- 



