5) Spleen of guinea-pig
1. Normal control
2. Enlarged (inoculated with Brucella abortus)

6) Brucella nodule on the liver. Granulomatous lesions composed of macrophages in center and surrounding accumulation of lymphocytes.

7) Detection of Brucella from the lymph nodes. Round, transparent,small colonies seen at 5 days of incubation.

8) Brucella abortus, rod-shaped bacilli often appear short rod shaped bacilli at the primary isolation.