260 



ASPHYXIA. 



1. The first opinion on this subject, which 

 need be noticed here, is that which was sup- 

 ported by the great Haller, viz. that the circu- 

 lation, and with it all other functions of the 

 body are brought to a stand, because when the 

 movements of respiration cease, and the lungs 

 are no longer dilated and contracted, there is a 

 mechanical difficulty to the propulsion of the 

 blood through the pulmonary capillaries, by 

 which the fatal stagnation in these vessels, ob- 

 vious on dissection, is produced. 



This doctrine was satisfactorily refuted by 

 Goodwyn, in his treatise on the Connection of 

 Life with Respiration, who shewed that the 

 air-cells of the lungs are not necessarily con- 

 tracted at the time of asphyxia, and that after 

 having once admitted air, these cells never are 

 so much emptied of it again, or contracted on 

 themselves, as to offer any considerable impe- 

 diment to the free motion of blood in their 

 parietes. Besides, we know that the same 

 stagnation in the lungs takes place in the case 

 of an animal confined in a gas which does not 

 contain free oxygen, as in the case of drowning 

 or strangulation, although in the former case, 

 any impediment to the mechanical acts of re- 

 spiration that can occur, must be the conse- 

 quence, not the cause, of the fatal changes 

 within the chest.* 



2. The well-known theory of Goodwyn him- 

 self on this subject was, that the venous blood 

 is not an adequate stimulus to the left side of 

 the heart, which in the natural state circulates 

 arterial blood only, and which fails to contract 

 upon or propel blood which has passed un- 

 changed through the lungs.f 



This doctrine was, in its turn, refuted by 

 Bichat, who showed by experiment that in the 

 case of strangulation the venous blood does 

 penetrate the lungs and left side of the heart, 

 and is delivered from the carotid arteries if 

 these are punctured ; that the appearance of 

 venous blood in these arteries is contemporane- 

 ous with what was described as the second 

 stage of asphyxia, viz. the insensibility and 

 spasms ; and further, his experiments have 

 been generally admitted as affording satisfac- 

 tory evidence, that the circulation of venous 

 blood through the brain is a sufficient cause for 

 these symptoms, and produces them when the 

 venous blood from the heart of one dog is sent 

 to the brain of another. J He also found by 

 experiment, that venous blood could be in- 

 jected artificially into the left cavities of the 

 heart, with the effect of exciting, not suppress- 

 ing their action . 



3. Bichat ascribed the cessation of the circu- 

 lation in asphyxia, however, not to the penetra- 

 tion of the brain by venous blood, and the 

 consequent insensibility (which is now well 

 known to be compatible with the maintenance 

 of circulation for many hours, provided the 



* This point has been further elucidated by some 

 experiments, of which an account was read, by 

 the author of this article, to the Medical Sections 

 of the British Association. 



t Connexion of Life with Respiration, p. 82. 



$ Recherches Physiologiques, &c. Art. vii. 



S Ilechcrehes, c. p. 327. 



blood can be arterialized,) but to the penetra- 

 tion of the muscular substance of the heart by 

 venous blood, sent to it by the coronary arte- 

 ries, and which he held to be equally (although 

 less rapidly) fatal to the vital action of this 

 organ, as of the brain or nerves. 



4. Later experiments and observations have, 

 however, shewn that this explanation likewise 

 is, in some measure, incorrect. In fact, while 

 the free flow of venous blood in the carotid 

 arteries of an asphyxiated animal was urged 

 with perfect fairness by Bichat,. as a refutation 

 of the theory of Goodwyn, it was with equal 

 justice argued by Goodwyn,* in opposition to 

 Bichat, that if the heart's actions ceased in 

 asphyxia, only because its substance is pene- 

 trated by venous blood from the coronary arte- 

 ries, these actions could not be restored by 

 blowing air into the lungs and arterializing the 

 blood there. 



Bichat, indeed, foreseeing this objection, 

 maintained that the artificial respiration never 

 is successful in restoring the circulation, unless 

 employed in the interval which, as was already 

 stated, always exists between the occurrence of 

 insensibility and the final cessation of the circu- 

 lation. But subsequent and careful observa- 

 tions (e.g. those of lioesler, Edinburgh Journal, 

 vol. xxiii) show that life has been restored, by 

 this means, after warm-blooded animals have 

 lain from twelve to seventeen minutes after 

 their immersion in water, i. e. until a time when 

 all observations made by laying open the chests 

 of similar animals show that their circulation 

 must have ceased. The records both of the 

 Humane Society in London und of a similar 

 institution in Paris, seem sufficiently to show 

 that resuscitation has occasionally taken place 

 in the human body after fifteen minutes' im- 

 mersion, f And we are therefore well assured 

 that the arterialization of the blood at the lungs 

 may, in some instances, restore the natural state 

 of the heart's action after the circulation has 

 come to a stand. 



Farther, although there is a laboured attempt, 

 by Bichat, J to explain the accumulation of 

 blood on the right side of the heart, and the 

 comparative emptiness of the left side, in as- 

 phyxia, consistently with his own explanation 

 of the failure of the circulation ; vet it seems 

 obvious, that if that explanation were correct, 

 the left side of the heart, receiving the venous 

 blood and contracting on it until it loses its 

 power from the penetration of its own fibres, 

 should be found after death distended with that 

 blood; and that the accumulation of blood 

 taking place in the lungs and right side of the 

 heart, indicates that the capillaries of the lungs 

 are the main seat of the cause which ultimately 

 stops the circulation. 



That this is really the fact has been more 

 unequivocally shown, first, by the experiments 

 by Dr. Williams, and afterwards by those of 



* In a paper, not published till after his death, 

 but contained in the Edin. Med. and Surg. Journal, 

 July 1830. 



t See Cyclopaedia of Practical Medicine, art. 

 Asphyxia. 



$ Kecherchcs, &c. art. 6. 



