Euparal is a well-known mounting medium used to protect specimens on a microscope slide. Like Hoyer’s medium, it has the benefit of an index of refraction (refractive index) that minimizes distortion when a specimen mounted with it is viewed through an optical microscope, and it provides a permanent base preserving specimens over the long term, achieving a permanent mount. Unlike Hoyer’s medium Euparal does not clear the specimen, leaving it in the state in which it is mounted. Euparal is solvent-based (Eucalyptol) making it resistant to humidity issues, such as drying time, that affect water-based mounting mediums. It has a pH of 10. Some of the components of Euparal are toxic in handling and breathing (refer to SDS for ingestion toxicity) with the odor of eucalyptus. It is flammable. Use all appropriate safety measures when working with Euparal. Refer to the relevant safety data sheet(s).