User talk:Dpa88

ive got some questions that i dont know the answer yet... 1. what is the deferent between internal and external quality control systems within a histology laboratory ? 2. Picric acid is used as a fixative and as a stain. In dry form it us a potential hazard,why? 3. why paraffin never recycled ? 4.what is the deferent between progressive and regressive staining techniques? 5. Why formalin buffered?