Studies on experimental silico-tuberculosis. Comparative study with dusts of varying contents of free silica.

Abstract

1. The tuberculous changes induced in the experimental silicoticlungs of rabbits were found perceptibly more aggravated than those in the control rabbits with simple tuberculosis. 2. In groups of animals subjected to nearly the same rounds of dust inhalation, the tuberculous lesions were somewhat more aggravated in the animals subjected to inhalation of dust with high silica content than those given low silica content, but the difference was rather slight. 3. In the groups made to inhale dust with the same silica content, the animals subjected to more rounds of inhalation showed higher aggravation of the tuberculous lesions, in number, size and tendency to exudative changes, than those subjected to lesser rounds of dust inhalation. 4. The higher accumulation of silica-dust carrying cells in the cases with higher aggravation of the tuberculous changes seems to suggest that in accounting for the development of silico-tuberculous lesions we must pay more attention to the total amount of silica, especially, the dysfunction of the phagocytes due to their satiation with silica particles, rather than to the content of free silica in the dust.