THE HIGHER BACTERIA 157 



Bouillon shows growth after 5 or 6 days' incubation at 37C. A whitish 

 flocculent sediment and a whitish surface pellicle forms without clouding the 

 medium. 



Glycerin bouillon cultures have the same appearance as plain bouillon 

 cultures. 



Gelatin. Small, round, white, glistening colonies appear after 5 or 6 days. 

 They continue to increase in size for several weeks and become yellowish in the 

 center. Growth is scant on this medium and it is liquefied very slowly. 



Glycerin agar shows growth in 2 or 3 days. At first small, wrinkled, dry, 

 white colonies appear; these coalesce and form a dry, wrinkled pellicle, which 

 may be white, yellowish- white or yellow; aerial hyphae appear as irregular 

 projections from the surface. 



Potato. Growth first appears similar to that on agar; the pellicle, as it 

 ages, is first yellow, then brown and finally black. 



Milk is not coagulated. 



Resistance. Streptothrix actinomyces is more resistant to most germicidal 

 agents than the tubercle bacillus. 



Toxin. Streptothrix actinomyces produces an intracellular toxin. 



Pathogenesis. Actinomycosis is most frequently seen in cattle, the site of 

 infection in most cases being the lower jaw. This results from eating grain or 

 grass covered with actinomyces. When taken into the mouth an abrasion of 

 the mucosa or a necrotic tooth offers a favorable site for infection; the organism 

 enters and the disease progresses. Its course is chronic and gradually a large, 

 hard swelling forms, a condition commonly known as "lumpy jaw;" eventually 

 suppuration occurs, then spontaneous evacuation. Pus oozes from the opening. 



Infection does not always involve the jaw. It may be localized in the tongue, 

 skin, peritoneum, pleura or lungs and septicemia or generalized infections have 

 been observed. 



When the lungs, pleura or peritoneum are involved the condition simulates 

 tuberculosis. In man conditions following infection are similar to those ob- 

 served in cattle. The disease affects, most frequently, those engaged in agri- 

 cultural occupations and the care of cattle. 



Horses, sheep, and hogs are sometimes infected and the disease can be pro- 

 duced in rabbits and guinea-pigs by inoculation. 



Usually secondary infection occurs; staphylococci, streptococci and other 

 organisms are nearly always present in the pus discharged from actinomycotic 

 lesions. 



In the sputum from pulmonary cases tubercle bacilli may be found, together 

 with Streptothrix actinomycosis, and should be sought for in such cases. 



Diagnosis. Fluid or pus from suspected cases should be carefully examined 

 for yellowish, hard granules. If any are found they should be crushed between 

 a slide and cover glass and examined for rosette-like masses of club-shaped 

 bodies and for filaments. If granules are not discovered, then the pus is smeared 

 on a slide and examined for rosettes. The suspected material must be examined 

 as soon after removal from the lesion as possible. 



