1973 Volume 42 Issue 4 Pages 218-227
The bacillus employed in the test was the 6th subculture, 2-month-old on the 1% egg yolk medium, of the supposed Hawaiian strain. Male mice of ddN strain were divided into 6 groups of 10 each and the groups were inoculated either subcutaneously or intravenously with each 3 different doses (2×10-1, 2×10-2, 2×10-3mg and 10-1, 10-2, 10-3mg). The mice inoculated were sacrificed at the end 4, 6, 9 and 11 months (Table 1).
Observation of gross diseases were made at necropsy. Spleens were weighed and their weight per gram of body weight were recorded. The internal organs, superfi-cial lymph nodes and local lesions were removed, homogenized, and then submitted to microscopic examination and cultural recovery (Tables 2 and 5). The Ziehl-Neelsen stained smears were rated not only for the number of acid-fast bacilli under oil-imme- rsion but also for relative numbers and maximum and minimum sizes of globi under low magnification (Tables 2, 5, 4 and 6). In some instances histopathologic examinationswere also performed (Table 3). The results obtained indicated that in the mice inoculated with each of the doses subcutaneously or intravenously there was gross and bacteriologic evidence of infection, supported in some by histopathologic evidence. The findings were more pronounced in the animals intravenously inoculated than in those subcutaneously inoculated. In either case, however, they showed a tendency to become more marked in the course of infection. It seemsed reasonable to conclude that the disease in mice was fairly consistently reproduced with the test organisms, even when small inoculum doses, such as 10-1, 10-2, and 10-3 mg were used.
