(From the Greek physiologos = the natural scientist) the title of an early Christian Greek text on natural science from between the 2nd to the 4th centuries. In a catalog, it presents about 50 minerals, plants, and animals, some of which are real, but some of which also stem from the realm of fantasy. The focus is not scientific, but religious and concerned with salvation-history by allegorically relating (supposed) characteristics from the animal kingdom to Christ and the Church (e.g. the deer as the enemy of the serpent corresponds to Christ who defeats the devil). The document became the model for later animal books, the so-called cf. Bestiaries.