The effect of formalin on leptospirae in calf urine

Abstract

The effect of 0.2 per cent and 0.5 per cent formalin on the morphology of leptospirae in calf urine held at room temperature (21-31 degrees C) and at 37 degrees C was studied by dark-field and Fontana staining methods. Except for heavily contaminated urine specimens, for which both the dark-flied and Fontana stain methods are advisable, dark-field illumination is preferable to Fontana staining for the detection of leptospirae.