Reassessment of Carrel's Immortal Tissue Culture Experiments

In the 1910s, Alexis Carrel, a French surgeon and biologist, concluded that cells are intrinsically immortal. His claim was based on chick-heart tissue cultures in his laboratory that seemed to be able to proliferate forever. Carrel's ideas about cellular immortality convinced his many contemporaries that cells could be maintained indefinitely. In the 1960s, however, Carrel's thesis about cell immortality was put into question by the discovery that human diploid cells can only proliferate for a finite period. As it was gradually recognized that chick cells only have a finite proliferative life span in vitro as well, historians and scientists alike attempted to identify experimental errors that could have led to the extremely long life of Carrel's "immortal" chick-heart tissue cultures. Those reassessments not only point out potential experimental mistakes in pioneer tissue culture work in the early twentieth century, but are also relevant to current discussions about the different life spans of germ line cells, embryonic and adult stem cells, normal somatic cells, and cancer cells.