Abstract
In a previous experiment*, several strains of tubercle bacilli of. the human type which were different from each other in their virulence were injected seperately or jointly into the anterior cham-ber of the rabbit's eye, and it became known that their pathogene-city becomes more intensified, when injected jointly than when inoculated seperately.
In the present experiments, the BCG strain together with a virulent strain of human type, both mixed in various ratios, was inoculated into the anterior chamber of rabbit's eye, and the tuber-culous changes developed in the eye and in other organs were observed.
The arrangement of the experiments and results obtained are as follows:
(1) The pathogenecity of the tubercle bacilli studied was compared by inoculations in the 5 following combinations:
I) 0.005mg. tubercle bacilli of human type.
II) 0.0005mg. tubercle bacilli of human type.
III) 1.0mg. BCG.
IV) 0.005mg. tubercle bacilli of human type+1.0mg. BCG.
V) 0.0005mg. tubercle bacilli of human type+0.1mg. BCG.
(2) The grade of tuberculous changes in the eye runs paral-lel with that in other organs. The pathogenecity was found the highest in IV, next in V, far lower in I and II, and the lowest in III.
(3) It was thus recognized that the pathogenecity of tuber-cle bacilli is more intensely displayed by the mixed inoculation than by the seperate infection.
(4) It is noteworthy that a quantity of BCG inefficient to cause any decided change, when inoculated by itself, shows a conspicuous pathogenecity, when inoculated jointly with an insig-nificant amount of virulent human strain of tubercle bacilli.
(5) It may be concluded, therefore, that the BCG strain, when inoculated together with a virulent strain, displays a marked pathogenecity rather than a preventive effect.
