(j) When a strong light is brought before the eye the pupil of the eye will not dilate or contract.
(2) The expert tests are those which a doctor or coroner might use to ascertain the fact of death. These tests are made with the stethoscope and the ophthalmoscope.
(a) By the use of the stethoscope the physician can hear the sounds of the heart and if there is the slightest sound he can detect it. In the absence of any sound the body is pronounced dead.
(b) By the use of the ophthalmoscope the physician is enabled to look into the pupil of the eye and if there is life he can see the blood circulating through the tiny capillaries of the retina. If he does not see this capillary circulation he is quite safe in saying the body is dead.
(c) Another method consists in the hypodermic or intravenous injection of certain substances, and ascertaining whether these substances have been dispersed throughout the body. If they have, then a circulation exists and life continues, although the pulsation of the heart may not be detected by auscultation. Among the substances recommended for injection are fluorescin, sodium iodide, lithium iodide and potassium ferro-cyanide. The injection of the small quantities as used will not cause death should the patient still be living.
Fluorescin is usually injected, one gramme dissolved with an equal weight of sodium carbonate in eight cubic centimeters of water, and the whole quantity injected hypodermically. If the circulation is persisting, the skin and the mucous membranes after a very few minutes assume a greenish color; about twenty minutes after the injection, the portion of the eye within the iris assumes a green color from penetration of the fluorescin into the vitreous and aqueous humors, and in the blood the fluorescin may be detected by the following method: One or two threads of cotton are passed under the skin in the form of a seton, and when saturated with blood are transferred to a test tube, and boiled with a little water. As the liquid clears the green color of the fluorescin becomes evident, if that substance has been absorbed into the blood.
(d) Another method for the distinction of real from apparent death consists in picking up a fold of the skin and compressing it with a pair of artery forceps. If the skin does not completely settle down, and if the fine furrows produced by the teeth of the forceps continue indefinitely, then death has occurred. Whereas, if the circulation is continuous, the fold and the marks of the forceps would disappear. Moreover, if death has occurred the portion of the skin compressed by the forceps assumes a parchment-like appearance.
(e) The electrical current affords a means of determining death. It is now known that the muscles, after cadaveric rigidity has set in, do not respond to electric stimuli. The faradic current will cause, when death has occurred, muscular contractions until a short time before post-mortem rigidity occurs. The faradic stimulus is lost first and the galvanic stimulus soon after. We may be enabled to approximate the time at which death occurred, for, if we find any response to either the faradic or the galvanic current, we know at once that post-mortem rigidity has not yet occurred.
No person should be buried as long as the muscles contract when stimulated by either the faradic or the galvanic current. If the electrical test were always applied before a death certificate was signed, there would be absolutely no possibility of a person being buried alive and the public would soon lose the morbid fear of such an occurrence.