Briefly stated, the impressive step which science has here taken, is the preservation of life in the heart and other organs so that these may be taken out of the body and yet kept alive for months. With smaller animals Carrel has even accomplished the actual transferrence of organs from one individual to another. As for the simpler bodily tissues, it now seems possible to preserve these indefinitely outside the body, not only alive but in excellent health and ready to reassume their functions in another body. GENEVIEVE GRANDCOURT THE "IMMORTALITY" OF TISSUES A very evident disadvantage under which medical science has labored has been the impossibility of watching the chemical process set in motion by substances introduced into the body. For this reason various experimenters, from time to time, have attempted to "grow tissues" artificially, in such manner that their development, functions, and decay--under both healthy and diseased conditions--might be studied under the microscope. The only way in which this could be done would be to take a piece of living tissue from the body, and cause its cells to multiply; tissue being made up of an aggregation of cells. Science has failed to produce a single living cell, that is, a cell which will undergo the process of nuclear division (growth) which is the prime condition of its being; and it seemed equally impossible to cause a cell already living to undergo the same process if deprived of the circulation of the blood. Therefore, when in 1910 it was announced that Dr. Alexis Carrel with his assistant, Dr. M. T. Burrows, had succeeded, scientific credulity was taxed. A well-known French savant expressed the opinion before the Society of Biology in Paris, that as others experimenting along these lines, had witnessed only degeneration and survival of cells, this phenomenon was all Carrel's discovery amounted to. In view of past experience, indeed, the chances were in favor of a mistake. In 1897, Leo Loeb said that he had produced this artificial growth both within and without the body. Obviously, such development within the organism where the process of utilizing the body-fluids, etc., follows the same course as in nature, takes on the character of grafting rather than of cultivating in a culture medium. As to causing the external growth, it was ten years later before it seems first to have succeeded. In 1907 Harrison, from Johns Hopkins University, furnished details of his research in such form as to be convincing. But his work had reference to the growth of tissues only of coldblooded animals, he having cultivated artificially, nerve fibers from the central nervous system of the frog.