points of his organs and his humors. Here it begins to corrupt the fluids, to disorganize the tissues, to destroy the equipoise and endanger the harmony. This process is more or less lingering and deceitful, and, when we note the manifest signs of death, we may be sure that the work lacked no deliberate preparation.
These ideas of Leibnitz, like most of the conceptions of genius, waited long after the time of their appearance for confirmation by demonstrative experiment. Before his day, bodies were dissected only for the sake of studying in them the conformation and normal arrangement of the organs. When this study was once completed, science took up the methodical inquiry into the changes produced in the different parts of the body by diseases. Not until the end of the eighteenth century did death in action become the subject of investigation by Bichat.
Bichat is the greatest of the physiological historians of death. The famous work he has left on this subject, his "Physiological Researches upon Life and Death," is as noteworthy for the grandeur of its general ideas, and its beauty of style, as for its precision of facts and nicety of experiment. To this day it remains the richest mine of recorded truths as to the physiology of death. Having determined the fact that life is seriously endangered only by alterations in one of the three essential organs, the brain, the heart, and the lungs, a group forming the vital tripod, Bichat examines how the death of one of these three organs assures that of the others, and in succession the gradual stoppage of all the functions. In our day, the advance of experimental physiology in the path so successfully traversed by Bichat, has brought to light in their minutest details the various mechanical processes of death, and, what is of far greater consequence, has disclosed an entire order of activities heretofore only suspected to be at work in the corpse. The theory of death has been built up by slow degrees along with that of life, and several practical questions that had remained in a state of uncertainty, such as that of the signs of real death, have received the most decisive answer in the course of these researches.
I.
Bichat pointed out that the complete life of animals is made up of two orders of phenomena, those of circulation and nutrition, and those that fix the relations of the living being with its environment. He distinguishes organic life from animal life, properly so called. Vegetables have only the former; animals possess both, intimately blended. Now, on the occurrence of death, these two sorts of life do not disappear at one and the same moment. It is the animal life that suffers the first stroke; the most manifest activities of the nervous system are those which come to a halt before all the rest. How is this stoppage brought about? We must consider separately the order of occur-
