A Note on Petroff's Cultural Method for the Isolation of Tubercle Bacilli from Sputum and Its Application to the Examination of Milk

1. Tubercle bacilli were isolated by the Petroff method from 64.8 per cent of the sputa which were found to be positive by the direct microscopic method. 2. The organism was recovered from 69.2 per cent of the samples of milk that were artificially infected. 3. Of the milk obtained through the New Haven Health Department Laboratory 8.4 per cent of the samples were found to contain tubercle bacilli, while none of the twenty-nine samples from the State Laboratory gave positive cultures. 4. All the guinea pigs (thirteen), except one, which were used as control animals died without any visible signs of tuberculosis. 5. Petroff's method for the isolation of tubercle bacilli from sputum may be applied successfully to the examination of milk. With slight modifications, the method should prove constant and reliable. The need of such a method for the examination of milk and milk products is apparent.