1931 ANNUAL REPORT, 1930 i7 



ranch has sufifered outbreaks on successive years it will be well to have a con- 

 siderable quantity of the bacterin prepared and to inject the foxes each year. 



LABORATORY PROCEDURES 

 Lobar Pneumonia 



Bacteriological Findings. — Stained smear of the bloody exudate oozing from 

 the cut lung surface shows gram-positive cocci both singly and in short chains. 

 A stained smear of the trachea shows both short-chain streptococci and grouped 

 gram-positive staphylococci. 



Blood agar culture plates of the cut lung surface showed pure culture of a 

 markedly hemolytic organism. Colonies are grey, tiny discrete and are sur- 

 rounded by a lake of hemolysis. Plates of the trachea show both hemolytic 

 and staphylococcus colonies. 



Animal Inoculation. — Rabbits injected intravenously in the ear vein with a 

 drop of the exudate oozing from the cut lung tissue died in 36 hours. A stained 

 smear of their heart's blood shows numerous gram-positive cocci arranged singly 

 and in short chains. An injection with heart's blood intravenously into two more 

 rabbits caused death in 18 hours. 



Cultural Characteristics. — The cultural characteristics are as follows: 



Agar slants — No perceptible growth. 



Blood agar — -Tiny discrete grey colonies in the centre of a lake of marked hemolysis. 



Colonies tend to remain separate, no spreading. 

 Broth- — Not good growth unless serum added, sediment. 

 Gelatin stab — Slight growth on surface, no liquefaction. 

 Litmus milk^Ac'id reaction, no curdling. 

 Potato slants — No growth. 

 Sugar reactions — Ferments dextrose, lactose, salicin with acid but no gas. No 



action in mannite, maltose, saccharose. 

 Staining — Gram-positive cocci. In tissue form short chains. 



Autogenous Bacterin. — Four blood agar slants and one tube of serum broth 

 planted with the hemolytic streptococcus isolated in pure culture from the lungs. 

 One agar slant of the Staphylococcus aureus isolated from the trachea. Growth 

 for 24 hours and then slants washed off with normal saline and mixed with the 

 broth tubes in sealed ampules and heated in water bath for one hour at 65° C. 

 A few drops of each ampule planted on blood agar plates as test for sterility. 

 No growth in 24 hours. Diluted with sterile normal saline to the required 

 strength and placed in sterile containers with rubber needle caps and 0.5 per 

 cent, phenol added as a preservative. 



The dose is 3^ c.c. two days apart to all exposed foxes. 



Control. — Injected fox pup placed in pen with a sick fox. The pup 

 showed no signs of disease although the sick pup died about 10 days after of 

 hemolytic streptococcus pneumonia. Shortly after the injections 7 immunized 

 pups escaped from their pen and dug into a pen where four pups had died of 

 pneumonia, the last one the day prior. The pups ate what feed remained in the 

 pen and stayed in the kennel over night, but all remained healthy. After the 

 entire ranch had been inoculated no further cases developed, although two pups 

 died while the bacterin was being prepared. One hundred and twenty-five 

 exposed fox pups and a few adults were treated with two 14 c.c. doses of the 

 bacterin given two days apart. 



