We have deemed it necessary to offer these few remarks upon the relations which subsist between the functions of the heart, lungs, and brain, in as much as the propositions which have been thus established respecting them, can alone lead to a correct pathology of those diseases, by which life is suddenly extinguished, or suggest a rational and effectual plan of treatment, in cases of suspended animation. SYNCOPE: In which the pulsations of the heart cease, before the action of the respiratory organs. The heart may cease to beat either from organic lesions in its own structure, or in that of its vessels; or from being sympathetically affected by injuries in other parts[20]; or from the operation of certain poisons; or from a shock of the general nervous system, as experienced in paroxysms of certain passions. In ordinary fainting it is evident that some slight and feeble motions of the heart still continue, although insufficient to produce a sensible pulsation in the more distant arteries; and where this has continued for an unusual period, and the respiration has been so obscure as to escape common observation, the phenomenon has been eagerly seized by the admirers of the marvellous, and credulity has attached to its history, under the name of _Trance_,[21] circumstances of extravagance and mystery, to which it can hardly be necessary to allude on the present occasion. But the motions of the heart may have ceased altogether, and in such cases it becomes a question, no less interesting to the practical physician than to the physiologist, whether they can ever be restored, and if so, we have to inquire under what limitation, as to time; under what circumstances; and by what means? The views which have been already offered respecting the pathology of Syncope will afford us considerable assistance in the solution of a problem, so intimately connected with inquiries of forensic importance. It would appear that where the heart has ceased to pulsate, _in consequence of the cessation of respiration, it can never again be set in motion_; but that where it has stopped from other causes, as from the operation of certain poisons, its muscular irritability not having been exhausted, its action may be occasionally revived. Where Syncope arises from hemorrhage, we shall find, on dissection, that the heart and its great vessels are either empty, or contain only a small quantity of blood in their cavities; but where Syncope arises from other causes, the heart is seen distended to an unusual magnitude, and the blood in the left auricle and ventricle is generally of a more or less florid colour, and has not the hue of venous blood; a circumstance which depends upon the pulsation of the heart ceasing before the function of respiration, and which is the very reverse of what happens in death from suffocation, as we shall hereafter explain.