There are certain types of beings who are capable of discerning the reality of the creatures of both the spirit and the material worlds. Belonging to this class are the so-called fourth creatures of the Havona Servitals. [1]
Every fourth servital is more physical in type than the others; that is, out of each thousand, seven hundred and fifty are apparently true to spirit type, but two hundred and fifty are semiphysical in nature. [2]