All types of bodies (animate and inanimate) which are found in this world, are formed by four Ustaqissat (elements) after mixing of with each other in different or in uniform quantities in accordance with the needs of the body. As a result of this mixing one quality dominates over the body, and this is called Mizaj.
If a compound is formed by the interaction of four elements with their equal quantities, a kafiat (quality) is produced in the compound which is known as Mizaje mo'tadil (equable temperament). And if a compound is formed after mixing of four elements with their unequal quantities, a quality produced in the compound, it will be Mizaj (temperament) of the compound. For example, if the dominant element (part) in the compound is Nar (fire), the compound would be considered as of Har Mizaj (hot temperament). Similarly, if the dominant element or part of the compound is Maa (water), the compound would be considered as of Barid Mizaj (clod temperament). And if, the dominant part of the compound is Hawa (air) that is called as of Ratab Mizaj (moist temperament). And if the dominant part or element in the compound is Arz (soil), the compound would be called as of Yabis Mizaj (dry temperament).
Similarly, if two elements out of four Ustaqissat (fire, air, water, soil) become dominant, the compound would be called by their names. For example, if fire and air both are dominant in the compound, it would be considered as Har Ratab. Like wise there are four types of Murakkab Mizaj as Har Ratab, Har Yabis, Barid Ratab and Barid Yabis.
There are 9 types of Mizaj , one is Mo'tadil and eight are Ghair Mo'tadil (Tibbi Mo'tadil).Because of intermixing of elements in different proportion in the compounds, numbers of Mizaj may exceed the 9 and can reach beyond the limit of counting.