An experimental inquiry into the pathology and treatment of asphyxia ... To which the Royal Humane Society awarded the Fothergillian Gold Medal / [John Eric Erichsen].

  • Erichsen, John Eric, 1818-1896.
Date:
1845
Catalogue details

Licence: Public Domain Mark

Credit: An experimental inquiry into the pathology and treatment of asphyxia ... To which the Royal Humane Society awarded the Fothergillian Gold Medal / [John Eric Erichsen]. Source: Wellcome Collection.

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    examined four hours after the trachea had been tied. All movement of the heart had then ceased, and the same appearances, as nearly as possible, were found as in the former case,—the difference in the quantity of blood on the two sides of the heart being but small. The same experiment repeated on other puppies of the same age was attended with similar results. In the asphyxia of very young animals it is quite evident, as has already been stated, that the circulation cannot be brought to a stand in consequence of any obstruction to the passage of the blood through the pulmonary capillaries, as the ductus arteriosus and fo¬ ramen ovale are still patent. This is also proved by the fact of both sides of the heart containing nearly an equal quantity of black blood. The cause of death must consequently be sought for in the heart; which organ conlinues acting until its irritability, which (like that of the muscular system generally in young warm-blooded animals with closed eyes) is very great, is exhausted by the continued circulation of black blood through its muscular fibres. For however low the vitality of a young puppy may be, yet the process of respiration is carried on to a certain extent ; it being necessary, as has already been stated, for the maintenance of life, that a certain quantity of arterial blood should circulate through the system. When this supply, com¬ paratively trifling as it may be, is cut off, the blood, becoming entirely venous, is rendered unfit for the supply of the wants of the system ; for although, as Edwards and Dr. Kay have shewn, venous blood may for a time keep up the contractility of the heart and oiher muscles, yet it is of course unable to do so for a continuance. The principal cause of the cessation of the circulation, then, in young warm-blooded animals born with their eyes closed, whilst the ductus arteriosus and foramen ovale remain open, appears to be the gradual diminution in the force of the heart’s contractions in con¬ sequence of the circulation of black blood through its muscular fibre. The following are the phenomena, then, of the cessation of the heart’s action in asphyxia:—When the access of atmospheric air is prevented, the blood continues to be supplied for a minute or two, apparently in its usual quantity, by the pulmonary veins, and the contractions of the heart are as strong and usually more frequent than natural. At about the second or third minute, when the blood has become perfectly venous in its characters, the frequency of the contractions falls very considerably, and the force of the propulsive power probably begins to be impaired. The alteration in the quality of the blood continuing, and the diminution in its quantity increasing, owing to causes that will presently be adverted to, the contractions of the ventricles become gradually weaker and weaker, as well as less frequent, and at about the ninth or tenth minute cease entirely; tremulous movements continuing in them, however, without distinct contractions, for some little time longer. 3. We now come to the consideration of the third class of opinions,