DEATH. 



797 



more sensible of the loss of blood, the nervous 

 symptoms, viz. vertigo and leipothymia, ap- 

 pear, and immediately afterwards the pulse 

 falls and becomes imperceptible. In corro- 

 boration of this fact we might at first be 

 inclined to mention that a diminution of the 

 quantity of the blood, so far from depressing 

 the circulation, often appears to excite it 

 violently, as in what has been denominated 

 hamorrhagic reaction; but in such instances 

 analogous effects have been also witnessed in 

 the cerebral functions, namely, delirium and 

 extreme sensibility, &c. On the whole we 

 may conclude with regard to both these sys- 

 tems that the depressing effect of haemorrhage 

 depends rather upon the suddenness of the 

 change, than upon the absolute diminution 

 of the quantity of the fluid. 



7. Syncope by poisons. Some substances 

 depress the action of the heart in the man- 

 ner to which we had occasion to refer when 

 speaking of syncope by mechanical injuries of 

 the tissues generally. Of this kind are the 

 mineral acids, oxalic acid, and the pure 

 alkalies. They produce death, when taken 

 in certain quantities, by means of that de- 

 pression of the circulation which follows 

 the destruction of the parts to which they 

 are applied. In smaller quantities they may 

 be more remotely fatal by exciting disease, 

 gastro-enteritis for instance. One of the sub- 

 stances mentioned, viz. oxalic ; acid, may in- 

 duce direct depression of the circulation, un- 

 attended by cerebral affection, even when its 

 chemical effect upon the stomach is prevented 

 by dilution. In this form it must be classed 

 with a large collection of substances which in 

 certain doses subdue the moving powers of 

 the circulation, without any previous coma, 

 without any alteration of the tissues, and 

 without any gastric irritation; such are arse- 

 nic in large quantities, tobacco, digitalis, and 

 most of the animal poisons. To the same 

 class belong those malarious and contagious 

 poisons which occasionally induce fatal syn- 

 cope before any of their ordinary effects upon 

 the general functions ; we scarcely need to 

 mention cholera, malignant typhus, plague, 

 scarlatina, &c. The narcotic substances mani- 

 festly act first upon the cerebro-spinal system ; 

 syncope follows either with or without as- 

 phyxia. Those which act rapidly appear to 

 strike the circulation before asphyxia has had 

 time to transpire ; we may instance hydro- 

 cyanic acid, essential oil of almonds, large doses 

 of opium and of alcohol, certain gases, par- 

 ticularly sulphuretted hydrogen and cyanogen. 



8. Syncope by cold and lightning. It is 

 not clear whether these outward agents arrest 

 the circulation through their influence upon 

 the nervous system, or by directly paralysing 

 the irritability of the fibres of the heart. 



9. Syncope by inanition. In cases of this 

 description it is probable that the failure of the 

 heart's action is a compound result of the 

 prostration of the nervous system, and of the 

 diminution of the proper stimulus of the 

 circulation. 



10. Syncope by disease. All fatal maladies 



must terminate in cessation of the heart'sa c- 

 tion, but we limit the present category to those 

 cases in which this event is unpreceded by 

 asphyxia. The others have been hinted at 

 under the head of syncope by asphyxia. The 

 diseases now under consideration may, we 

 think, be conveniently arranged as follows : 

 I. Those which stop the motion of the heart 

 by obstructing its mechanism, e. g. collections 

 of fluid in the pericardium, lesions of the val- 

 vular apparatus ; accumulation of fat, &c. ; or 

 by diminishing the contractility of the fibres, 

 e.g. atrophy, or degeneration of the muscular 

 substance;* or by perturbing in some unex- 

 plained manner the nervous influence, e. g. the 

 functional form of angina pectoris. 2. Those 

 which are attended with haemorrhage, e. g. 

 aneurisms, and diseases of mucous surfaces. 

 3. Those which induce excessive and long-con- 

 tinued discharges. Thus fatal syncope has sud- 

 denly terminated a fit of diarrhoea; but it must be 

 borne in mind that in such instances the power 

 of the circulation had previously been greatly 

 enfeebled either by deterioration of the blood, 

 or by causes acting on the innervation of the 

 heart, or by the existence of irritation in some 

 part of the system. 4. Diseases implicating 

 the cerebro-spinal organs. Some of these ope- 

 rate in the same manner as those accidental 

 injuries which produce concussion, and which 

 have been already adverted to. Thus in that 

 species of apoplexy which terminates instan- 

 taneously, (apoplexie foudroyante of French 

 authors,) the sanguineous extravasation appears 

 to have the same effect as a mechanical shock 

 to the whole nervous mass. The more common 

 form of apoplexy extinguishes life by impeding 

 the respiratory movements. We have more 

 than once known cases of structural disease of 

 the brain terminate by sudden syncope, but 

 have learned nothing from the necroscopy 

 capable of explaining why the fatal occurrence 

 took place at the precise time when it did, 

 rather than at any other moment in the period 

 during which the disease had existed ; though 

 it was easy to conceive that a lesion of this 

 description must have been competent at any 

 time to produce such changes in the cere- 

 bral circulation as would induce the result 

 in question. 5. Diseases attended with what 

 has been vaguely called irritation, either short 

 and intense, or moderate but long-continued. 

 This irritation consists sometimes of inflam- 

 mation and its sequelae, and sometimes of spe- 

 'cific structural alterations. A good illustration 

 of the former of these is afforded by peritonitis, 

 which frequently cuts off the patient by sub- 

 duing the action of the heart, long before this 

 effect could transpire from derangements of the 

 organs contiguous to the seat of disease. Still 

 more remarkable in this point of view are the 

 effects of acute inflammation of a synovial 

 capsule. It is true that these affections are 

 accompanied by violent pain, which might be 

 said in common language to exhaust the 

 powers of the system, or in stricter phrase, to 



* See Mr. Chevalier's interesting cases of sudden 

 death in the Mod. Ch. Trans, vol. i. 



