Death in its most restricted sense may be defined to be that condition which imme diately succeeds the abolition of all those ac tions or properties which distinguish living from brute matter, a condition not merely negative but privative. But death is likewise applied to certain states of the organic system in the higher animals, in which the abolition of the functions is not universal. In the former sense, an animal is not dead until every vital action throughout the tissues has been extinguished; while in the latter, dis solution is considered to have taken place -when the circulation and respiration have ceased, because the cessation of the others almost uniformly follows. We have here then an obvious distinction of Death into two kinds, which will be found to correspond with a very natural division of the vital actions into two classes ; 1, those which transpire between the particles of which living bodies are composed (nutrition and contraction); and 2, those which occur between certain collec tions of organic particles, called organs, and by virtue of which these organs constitute a whole system—(respiration, circulation, inner vation, &c.) The extinction of the former of
these classes of functions we shall venture to designate Molecular Death ; of the latter, Systemic Death.* The following truths respecting the mutual influence of these two kinds of death will be illustrated in the course of the present article : 1st, That molecular does not necessarily in volve systemic death, unless the former is universal. 2dly, That when partial, as in mortification, the tendency of molecular to in duce systemic death depends on the import ance of the part to the whole. 3dly, That molecular death in one part can only induce the same change in another part, by means of its interference with one of the systemic func tions. 4thly; That systemic death must neces sarily be followed sooner or later by molecular death,—but that, 5thly, The reality of systemic death can only be proved with certainty by the occurrences pertaining to molecular death.