William Fraser

“ In man it is quite different: the animal functions may be suspended, and even some of the organic processes interrupted, without extinguishing life, but there are certain of his functions the cessation of which for a limited period must inevitably cause death. ”

“ The innervation test is rendered practicable through the inseparable connection of this attribute with muscular contraction; for, even if contractility is inherent in muscle, its excitation is possible only through the incorporation of nerve-elements. As this manifestation of nervo-muscular energy can always be sensibly excited by electrification during the persistence of the feeblest vitality, the utter failure to obtain such a result in parts the activity of which is essential to life, affords conclusive evidence of vital extinction. ”

“ For, though certain cold-blooded animals can exhale a sufficient quantity of this product through their skin to permit a reduced vitality, in man such a cutaneous transpiration is exceedingly minute and altogether inadequate to the maintenance of life, and it may continue even after death as a merely physical property of tissue. ”

“ But, in higher organisms, life is indissolubly associated with certain accessory processes, and, in these cases, though the molecular interactions on which its essential attributes immediately depend are directly imperceptible, yet it is possible to prove its existence or non-existence by sensibly demonstrating the presence or absence of these its inseparable concomitants. ”

“ Cardiac contractions are also necessary to propel the corpuscles into the capillaries, as the attraction of the tissue-elements for these minute bodies can act only at insensible distances.
Man's structure conceals the changes which occur within the minute blood-vessels, but some animals admit the examination of the interior processes which accompany and conduce to the external manifestations of capillary congestion. Observing the circulation in the web of the frog's foot under the microscope, fluctuations in its current are noticed independent of the heart's action. ”

“ Innervation is blended with and controls all the vital operations, being conspicuously implicated with muscular contraction, an act primarily concerned in the various movements of respiration and circulation. The frequently-repeated transmission of intense electric currents is the most powerful stimulus of contractility, and, when such a measure fails to excite contraction in muscles essential to life, death must have occurred. ”

“ As there are means of artificially exciting preternatural activity of the circulation to a recognizable extent, in parts open to observation, during the minimum degree of vitality, such a possibility affords a reliable method of infallibly deciding in any particular case as to the existence or non-existence of this vital process. ”

“ Hold the flame of a candle close to (but not in contact with) the skin sufficiently long to render the cuticle easily detachable from its subjacent connections: if the body is dead, the parts beneath will present a crisp, yellowish-white, horny appearance, unaffected by pressure; if alive, there will be readily perceptible a vital redness, distinguishable from all post-mortem discolorations by its repeated displacement and reappearance under alternating pressure by tip of the finger or otherwise. ”

“ Active tissues, during their development, appropriate a store of energy which, at maturity, they are capable of instantly expending in the manifestation of their special powers. Such exertions are inevitably attended by degradative transformations of their material elements. ”

“ Thus, although eight is important to comfort, it may be lost without affecting vitality; the hepatic function may be vicariously performed; even the renal secretion may be suspended for a considerable period without death: but the complete cessation of any of the essential functions of circulation, innervation, or respiration must be speedily followed by such a result. By the circulatory forces, a constant flow of blood is directed to and from all the parts ”

“ Yet organisms are never sufficiently independent to spontaneously evolve such progressive results, but require the constant accession of extrinsic energy to develop their included potentialities.
The sun is the physical source of extraneous energy for every species of vital change occurring on the earth's surface, as through the immediate agency of its rays vegetables are enabled to abstract from the surrounding medium those elements adapted to their special needs ”

“ An essential characteristic of living bodies is their power of actively maintaining a degree of varying integrity of constitution in opposition to destructive influences. This requires the incorporation of extraneous materials and their conversion into definite specific structures, and always involves the immediate apposition of ingredients, as well as a reciprocal state of the parts to be nourished. Although such intimate reciprocation of living structures and nutrient materials must always exist, the means whereby it is effected varies exceedingly in different instances. ”

“ The entire absence of such distinctive physiological reactions and the occurrence of merely physical alterations, under the proper use of these respective measures, is undeniable proof of death. Over the heart is the most suitable region whereon to operate, as there the skin longest retains its vital warmth ”

“ In the lower order of beings it is accomplished very simply, the medium which they inhabit offering directly the requisite pabulum, which their own condition enables them to assimilate without any preparatory elaboration. In more complex organisms a definite correlation of parts is necessary to elaborate the crude materials of food, as well as to bring them into immediate relation with the various tissues. ”

“ The validity of the respiratory test results from the fact that even during the most reduced state of vitality carbonic acid is perpetually generated in the system, and extricated therefrom through specially adapted air-passages, where its escape can invariably be detected by proper appliances. ”

“ As to their vital significance, man's functions may be classified into essential and supplemental—the former including such as can not be discontinued beyond a brief interval without fatal consequences, the latter such as may be suspended or even destroyed without involving general dissolution. ”

“ A SATISFACTORY definition of life should express conditions involved in every phase of vital development, but never identified with any mode of inanimate existence. Transmutation represents one such fundamental distinction between animate and inanimate objects ”

“ By increasing the heat or prolonging its action the color becomes more distinct, till at the point of greatest intensity the cuticle becomes detached from its subjacent cutis by the gradual exudation and accumulation of a fluid which thus forms a true vesicle. ”

“ Cardiac movements and their associated vital coördinations involve the expenditure of nervo-muscular energy, and consequent production of simpler compounds, such as carbonic acid, the undue retention of which in the blood would cause certain death. ”

“ In some simple forms vital action may be suspended indefinitely by desiccation, being restorable by moisture, and even in some higher cold-blooded animals a state of temporary negation may be induced by congelation, the vital powers returning concurrently with the absorption of heat. ”

“ Similar gangrenous appearances may occur during life, but, besides their more circumscribed extent, the invariable presence of a line of displaceable redness at the confines of the living tissues is a constant and characteristic distinction. ”

“ Allowing a few hours to elapse after apparent death, so that an equilibrium may be established between the carbonic acid in the air-chambers and the atmospheric air, if death is real the amount of this product exhaled from the anterior opening of the air-passages will exactly correspond with that transpiring from an equal area of the skin ”