The Nobel prize in medicine for 1912 has just been awarded to Dr. Alexis Carrel, a Frenchman, of Lyon, now employed at the Rockefeller Institute of New York, for his entire work relating to the suture of vessels and the transplantation of organs. The remarkable results obtained in these fields by various experimenters, of whom Carrel is most widely known, and also the wonderful applications made of them by certain surgeons have already been widely published. The journals have frequently spoken lately of "cultures" of tissues detached from the organism to which they belonged; and some of them, exaggerating the results already obtained, have stated that it is now possible to make living tissues grow and increase when so detached. Having given these subjects much study I wish to state here what has already been done and what we may hope to accomplish. As a matter of fact we do not yet know how to construct living cells; the forms obtained with mineral substances by Errera, Stephane Leduc, and others, have only a remote resemblance to those of life; neither do we know how to prevent death; but yet it is interesting to know that it is possible to prolong for some time the life of organs, tissues, and cells after they have been removed from the organism. The idea of preserving the life of greater or lesser parts of an organism occurred at about the same time to a number of persons, and 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.