In situ

Refers to performing assays or manipulations with intact tissues.

In the natural place or in the original place. 1. Experimental treatments performed on cells or tissue rather than on extracts from them. 2. Assays or manipulations performed with intact tissues.

(in si'too) the natural or normal place; confined to the site of origin without invasion or spread to neighboring tissues.

In the original situation.

In its natural position or place; unmoved, unexcavated, remaining at the site or subsurface.