1870-1959

American zoologist who improved tissue-culture techniques. Receiving a doctorate from Johns Hopkins University, Harrison focused on embryology experiments. He was particularly interested in the development of the nervous system. Harrison observed the growth of frog nerve fibers, proving that cultured tissues could grow independently of the body. He encouraged medical applications of this discovery. Harrison also was interested in the symmetry of developing embryos. He experimented with grafting cells to host embryos to determine how this transfer affected growth.