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The movement of cells or organisms toward or away from a substance in response to its concentration gradient.

Reaction of living protoplasm to a chemical stimulus, whereby the cells are attracted (positive c.) or repelled (negative c.) by acids, alkalies, or other bodies exhibiting chemical properties; chemiotaxis, chemotropism.

The sensitiveness of cells or micro-organisms to chemical stimulus, which is either attractive or repellent, exhibiting respectively positive or negative chemotaxis.

The movement of certain cells toward or from other cells.

The property of cellular attraction or repulsion due to the effect of certain chemical agents. Bacteria or their dead protein products will attract the leukocyte, and will even cause it to emigrate from the vessel into the tissues.