nd
though the ends in view have been quite different, the investigations
have led to essentially similar results. The surgeons who for a long
time have transplanted various organs and grafted different tissues,
bits of skin among others, have sought to prolong the period during
which the grafts may be preserved alive from the time they are taken
from the parent individual until they are implanted either upon the
same subject or upon another. The physiologists have attempted to
isolate certain organs and preserve them alive for some time in order
to simplify their experiments by suppressing the complex action of the
nervous system and of glands which often render difficult a proper
interpretation of the experiments. The cytologists have tried to
preserve cells alive outside the organism in more simple and
well-defined conditions. These various efforts have already given, as
we shall see, very excellent results both as regards the theoretical
knowledge of vital phenomena and for the practise of surgery.

It has been possible to preserve for more or less time many organs in a
living condition when detached from the organism. The organ first tried
and which has been most frequently and completely investigated is the
heart. This is because of its resistance to any arrest of the
circulation and also because its survival is easily shown by its
contractility. In man the heart has been seen to beat spontaneously and
completely 25 minutes after a legal decapitation (Renard and Loye,
1887), and by massage of the organ its beating may be restored after it
has been arrested for 40 minutes (Rehn, 1909). By irrigation of the
heart and especially of its coronary vessels the period of revival may
be much prolonged.

The first experiments with artificial circulation in the isolated heart
were made in Ludwig's laboratory, but they were limited to the frog and
the inferior vertebrates. Since then experiments on the survival of the
heart have multiplied and become classic. Artificial circulation has
kept the heart of man contracting normally for 20 hours (Kuliabko,
1902), that of the monkey for 54 hours (Hering, 1903), that of the
rabbit for 5 days (Kuliabko, 1902), etc. It has also enabled us to
study the influence upon the heart of physical factors, such as
temperature, isotonia; chemical factors, such as various salts and the
different ions; and even complex pharmaceutical products. Kuliabko
(1902) was even able to note contractions in