Abstract
Bacillus pilifarmis antigens were demonstrated in smear preparations from infected mouse livers by direct immunofluorescence technique. Mouse serum antibodies against B. pilifarmis were demonstrated by indirect immunofluorescence technique. The test was employed quantitatively both on sera from experimentally infected mice and on sera from clinically healthy mice from colonies infected with B. pilifarmis, and could be used for the quantitative demonstration of antibodies in sera from a stock of rabbits with Tyzzer's disease. It was found very useful for the detection of subclinical infection.