announced at such frequent and brief intervals that we fail to note them all for lack of time, when haste and rush characterize habits alike of life and thought, do we find that we simply must stop, as it were for breath, while we unload a large amount of accumulated mental rubbish and clear a space in our storage capacity for up-to-date knowledge! It is a decennial mental house-cleaning process. We must unlearn so much of that which ten to forty years ago we so laboriously learned. We must adopt new and improved reasoning processes. But it is hard to do all this. For instance, as a boy I learned the old chemistry quite thoroughly. During a subsequent interval, when I did not need to study it, came the new chemistry, and when I again required it I had not only to study a practically new science—which was not so bad—but to rid my brain of much that had really found firm lodgment there, and this was difficult or impossible. So it is with one who, having been brought up on Euclidean geometry, finds himself confronted with the comparatively new non-Euclidean, and who has then not merely to forget, but to unlearn all those fundamental axioms which seemed so plain and so indisputable, that is, if he would accept the teachings of Bolyai and others. For example, that a straight line is not necessarily the shortest route between two points shocks our Euclidean orthodoxy, and is at the same time, to us, inconceivable; as also that parallel lines indefinitely prolonged may touch, and the like; likewise the concept of four-dimensional spaces, or worse yet, n-dimensional. And now, in somewhat like manner and to a certain degree, must we revise our previous conceptions of death, at least to this extent: Not that we yet know much better than we did what it really is, but that we know more about what it is not. Even save, perhaps, in its instantaneous happening it is but a step toward dissolution, usually not the first, certainly not the last, but yet the most conspicuous.

Death is in many respects a biochemical fact. It is so intertwined with ionic changes in the arrangement of matter that we may hope for more information regarding some of its aspects as knowledge of the latter accumulates.

But, evidently, we need to clarify our notions as we rearrange our facts. Somatic death is, after all, a most complex process. It may be shortened by instant and complete incineration, but scarcely in any other way. Even dynamite would scarcely simplify the problem. As to conscious death, that is probably (though not certainly) a matter of seconds only or possibly fractions of a second. While we have no accurate appreciation of what constitutes consciousness, nor even just where it resides, the central nervous system appears to be its most probable seat. But conscious death may occur almost instantly without injury to this system, as when a bullet passes through the thorax and the heart, without injuring the spine.

But what is it that suddenly checks all concerted and interdependent activity? Or does something or some controlling agency suddenly leave the body?

A recent theory, having features to commend it, is to the effect that life is a property or a feature of the ultimate corpuscles which compose the atom. Since these corpuscles bear to their containing atom a relative size comparable to that of the tiniest visible insect winging its way in a large church edifice, the intricacies of this particular theory readily appear. But it does seem as though among ourselves life has much to do with the hitherto neglected and despised nitrogen atom or molecule, since life inheres par excellence in nitrogen compounds. Moreover, vitality is conspicuously a feature of those chemical elements which have the lowest atomic weight, while at the other end of the table of atomic weights stands radium, of whose destructive emanations I have already spoken.

Another phase of the general subject of thanatology was suggested especially by Osier, who a few years ago called attention to the fact that but few, if any patients really die of the disease from which they have been suffering. This is not a paradox, and needs only reason and observation to confirm it. His statement was a preliminary to the consideration of terminal infections and toxemias, which of itself would be sufficient to erect thanatology into a dignified special study. Take, for instance, a patient who has long suffered from diabetes. The end is characterized by coma, i. e., an evidence of profound toxemia, and is in large measure due to acetonemia. A patient with chronic Bright's disease dies of uremic poisoning, or one with pneumonia dies of genuine heart-failure. The terminal stage of cancer is, again, toxemia of one kind or another, according as it has interfered with digestion, with respiration, or some other vital function, or has broken down, thus saturating the patient with septic products.

This aspect of the subject will bear any amount of study and elaboration, and its mention here should be sufficient for my purpose. Accordingly as it is properly appreciated, it will be recognized as having an important practical bearing, since, if we may foresee the direction from which the final danger threatens, it may be the better and the longer averted.

Another very important and practical subject is wrapped up in this one, namely, the utilization of apparently dead, or at least of only potentially living material (tissue) in the various methods of grafting or transplantation, which are to-day a part of the surgeon's work. The methods are themselves a transplantation of experiences gained by work in the vegetable kingdom. What wonder that the marvels revealed in one department should have incited work along parallel lines in the other? That flowers and fruit of one kind may be made to grow on a tree of a very different kind excites but a small amount of the astonishment it deserves, mainly because it is now a common occurrence, though properly regarded it might seem a miracle.

Differing only in minor respect is, for example, the removal of thyroidal tissue from one human being and its implantation into another, with functional success. One may ask just here, how is this matter concerned with thanatology? And the reply is: If this tissue were taken from a fresh corpse it would be by most people regarded as dead tissue. If so, does the dead come to life? Without violating the proper scientific use of the imagination one may fancy something like the following: Let a healthy young woman meet accidental and instantaneous death. It would be possible to use no inconsiderable portion of her body for grafting or other justifiable surgical procedures. The arteries and nerves could be used, both in the fresh state, and the former even after preservation, for suitable transplantation or repair work on the vascular and nervous systems of a considerable number of other people. So also could the thyroid, the cornea, the ovaries and especially the bones. All the teeth, if healthy, could be reimplanted. With the thin bones, ribs especially, plastic operations—particularly on the noses—of fifty people could be made. And then the exterior of the body could be made to supply any amount of normal integument with which to do heterologous dermatoplastic operations, or would furnish an almost inexhaustible supply of epidermis for Thiersch grafts, which latter material need not be used in the fresh state, but could be preserved and made available some days and even weeks later. A portion of the muscles might possibly be made available for checking oozing from bleeding surfaces of others, if used while still fresh and warm, and possibly portions of the ureters or some other portion of the remains