ating the process, the tissues would begin to grow again; but
their life even under these circumstances was limited at the most to
twenty days. This was manifestly too short a time in which to study the
fundamental questions to which the researchers had addressed
themselves. Thereupon, study was taken up to determine the question as
to _what made these tissues die_. It was found that, apparently as
incidental to growth, there was the process of decay, due to an
_inability of the tissues to eliminate waste products._

On January 17, 1912, experiments were commenced to determine whether
these effects could be overcome. The observations were on the heart and
blood-vessels, artificially grown, of the chicken fetus. These growths
were put into a salt solution for a few minutes at different periods of
their growth, and then placed in a new plasmatic medium. It was found
that by following this method, the tissues could be made to live
indefinitely. When an animal is in the early stages of its development,
the growth of its tissues is necessarily greater as it matures, there
being steady diminution after a certain age until the growth altogether
ceases, and the size of the animal is determined. But it was found by
subjecting these artificial growths to washings in salt solution that
the mass was _fifteen times greater at the end of than at the
commencement of the third month, showing that they do not grow old at
all!_ In the artificial growth the problem of senility and death is
solved.

It was the announcement of this "permanent life of tissues" that caused
such a furor in Paris last summer, and several eminent scientists to
demand ocular demonstration, because "the discovery, if true,
constituted the greatest scientific advance of a generation."

The following summary of this interesting and vitally important and
epoch-making work of Carrel is translated from an article published in
Paris recently by Professor Pozzi, who witnessed the experiments:

"Carrel found that the pulsations of a fragment of heart, which had
diminished in number and intensity _or ceased_, could be revived to the
normal state by a washing and a passage. In a secondary culture, two
fragments of heart, separated by a free space, beat as strongly and
regularly. The larger fragment contracted 92 times a minute and the
smaller 120 times. For three days, the number and intensity of the
pulsations varied slightly. On the fourth day, the pulsations
diminish