Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A Nissl body (or Nissl granule or tigroid body) is a large granular body found in neurons. It was named after Franz Nissl, German neurologist (1860-1919). Nissl bodies can be demonstrated by a method of selective staining developed by Nissl (Nissl staining), using an aniline stain to label extranuclear RNA granules. This staining method is useful to localize the perikaryon, cell body, as it can be seen in the soma and dendrites of neurons, though not in the axon or axon hillock. RNA stains blue with this method due to its basophilic (lat. "base-loving") properties.