just type in "chicken heart study" in google
From Wiki:
Carrel was also interested in the phenomenon of senescence, or aging. He claimed that all cells continued to grow indefinitely, and this became a dominant view in the early twentieth century.[6] Carrel was especially famous for an experiment[7] begun on January 17, 1912. To defend his idea, Carrel placed tissue cultured from an embryonic chicken heart in a stoppered Pyrex flask of his own design, and maintained the living culture for over 20 years with regular supplies of nutrient. This was longer than a chicken's normal lifespan. The experiment, which was conducted at the Rockefeller Institute for Medical Research, attracted considerable popular and scientific attention.
Carrel's famous experiment was never fully replicated (although other researchers obtained mutated "immortal" strains), and in the 1960s research by Leonard Hayflick and Paul Moorhead proposed that earlier researchers were wrong, and that differentiated cells can only undergo a limited number of divisions before dying. This is known as the Hayflick limit, and is now a pillar of biology.[6]
It is not certain how Carrel obtained his anomalous results. Leonard Hayflick suggests that the daily feeding of nutrient was continually introducing new living cells to the alleged immortal culture.[8] J. A. Witkowski has argued that,[9] while "immortal" strains of visibly mutated cells have been obtained by other experimenters, a more likely explanation is deliberate introduction of new cells into the culture, possibly without Carrel's knowledge.[10]
