MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 741 



about forty-eight hours small whitish to yellowish colonies appear. Growth has 

 been observed in broth in eighteen to twenty-four hours, on gelatin in eight or nine 

 days, and the latter is not liquefied. It has been found to grow on acid potato and 

 in acid or alkaline urine. 



Human beings and animals eliminate the organisms in the urine,' and 

 the milk of goats has been found to be a prolific source of infection. 

 With proper regulations in regard to goats' milk the disease has been 

 greatly reduced. 



Staphylococcic Infections* 



Boils, Abscesses, Wounds, Osteomyelitis, Pyemia, Etc. 

 Micrococcus pyogenes var. aureus, etc. 



Infections of this order are found throughout the world and because 

 of the association of staphylococci and streptococci with the large 

 majority of purulent inflammations, these organisms are called the 

 pyogenic cocci. 



No specific disease is produced, but chiefly boils, circumscribed 

 abscesses, infected wounds, osteomyelitis, pyaemia, etc. The symptoms 

 alone will not indicate, whether staphylococci or streptococci are 

 present, but a low grade of infection with more pus and less constitu- 

 tional disturbance tends to indicate the former, and staphylococci tend 

 to pyaemia rather than to septicaemia. 



Pasteur, Koch, Ogston and Rosenbach established the importance 

 of these organisms. 



Staphylococci in pus stain readily with aniline dyes. Pure cultures 

 can be obtained by plating or streaking on plain nutrient agar. 



While several different forms are found in pathological conditions, 

 the M. pyogenes var. aureus is by far the most frequent, and it is de- 

 scribed here as a type. 



M. pyogenes var. aureus is a spherical coccus about 0.7/i to 0.9;^ in diameter though 

 forms 0.4/i to i.2/i have been noted. On solid media the organism may be found 

 solitary, in pairs, or in rows of three or four, but characteristically in irregular groups 

 like bunches of grapes. In liquid media the single and paired arrangement is most 

 frequent. No spores, no capsules and no flagella are found; the organism shows 

 marked Brownian movement, like other cocci; Gram-poSitive. The temperature 

 range of growth is from about 10° to 43° with an optimum about 30°. Aerobe and 



• Prepared by Edward Fidlar. 



