We ask the following database query: How are the various types of ritual impurities caused? The reader is encouraged to perform the query using a standard Biblical Konnkordance or search engine. This database query yields the list below. The list justifies the following Rashi-Midrashic inference: Most types of ritual impurity are caused by world events such as death and sexual discharges. However leprous ritual impurity in addition to a world event - e.g. the white skin patches with white hair - also requires a declaration of a priest to create the ritually impure state. That is a white patch with white hair is in and of itself not ritually impure until a priest declares it ritually impure. This contrast - leprous vs other ritual impurities - is textually indicated by a phrase peculiar to leprosy, ....and the priest shall declare it impure... a phrase which occurs with no other ritual impurity, implying that priestly declaration is a prerequisite for creation of the ritually impure status. The list below presents the results of the database query.