The regeneration of specific tissue in a variety of organisms due to loss or death of the existing tissue.

Morphallaxis is the when some living things regenerate or regrow tissue after the original tissue dies. The word comes from the Greek allazein, which means to exchange.

For example, if a Cnidarian hydra, a microscopic animal, is cut in half, two new hydra grow.

Around the year 1930, scientists Wilson and Child showed that if the hydra was smashed to pulp and put through an instrument with tiny holes in it to separate each cell individually but without breaking any one cell, the hydra completely reformed itself.

Most tissue in Morphallaxis grows from material already present material. Not much new tissue is created .