538 OP RESPIRATION. 



576. It cannot be necessary here to dwell upon the fact, that by the repeated 

 passage of the same air through the lungs, it may, though originally pure and 

 wholesome, be so strongly impregnated with carbonic acid, and may lose so 

 much of its oxygen, as to become utterly unfit for the continued maintenance 

 of the aerating process; so that the individual who continues to respire it, 

 shortly becomes asphyxiated. There are several well-known cases, in which the 

 speedy death of a number of persons confined together has resulted from neglect 

 of the most ordinary precautions for supplying them with air. That of the 

 " Black Hole of Calcutta," which occurred in 1756, has acquired an unenviable 

 pre-eminence, owing to the very large proportion of the prisoners, 123 out of 

 146, who died during one night's confinement in a room 18 feet square, only 

 provided with two small windows ; and it is a remarkable confirmation of the 

 views formerly stated ( 210), and presently to be again adverted to, that of 

 the 23 who were found alive in the morning, many were subsequently cut off 

 by " putrid fever." Such catastrophes have occurred even in this country, from 

 time to time, though usually upon a smaller scale ; there has happened one at 

 no distant date, however, which rivalled it in magnitude. On the night of the 

 1st of December, 1848, the deck-passengers on board the Irish steamer London- 

 derry were ordered below by the Captain, on account of the stormy character 

 of the weather ; and although they were crowded into a cabin far too small for 

 their accommodation, the hatches were closed down upon them. The consequence 

 of this was, that out of 150 individuals, no fewer than 70 were suffocated before 

 the morning. 



577. It cannot be too strongly impressed upon the Medical practitioner, 

 however, and through him upon the Public in general, that the continued respi- 

 ration of an atmosphere charged in a far inferior degree with the exhalations 

 from the Lungs and Skin, is among the most potent of all the "predisposing 

 causes" of disease, and especially of those zymotic diseases whose propagation 

 seems to depend upon the presence of fermentable matter in the blood. That 

 such is really the fact, will appear from evidence to be presently referred to ; 

 and it is not difficult to find a complete and satisfactory explanation of it. For, 

 as the presence of even a small percentage of carbonic acid in the respired air, 

 is sufficient to cause a serious diminution in the amount of carbonic acid thrown 

 off and of oxygen absorbed ( 561), it follows that those oxidating processes 

 which minister to the elimination of effete matter from the system must be 

 imperfectly performed, and that an accumulation of substances tending to putre- 

 scence must take place in the blood. Hence there will probably be a considera- 

 ble increase in the amount of such matters in the pulmonary and cutaneous 

 exhalation ; and the unrenewed air will become charged, not only with carbonic 

 acid, but also with organic matter in a state of decomposition, and will thus 

 favor the accumulation of both these morbific substances in the blood, instead 

 of effecting that constant and complete removal of them, which it is one of the 

 chief ends of the respiratory process to accomplish. It has been customary to 

 consider the consequences of imperfect respiration, as exerted merely in pro- 

 moting an accumulation of carbonic acid in the system, and in thus depressing 

 the vital powers, and rendering it prone to the attacks of disease. But the 

 deficiency of oxygenation, and the consequent increase of putrescent matter in 

 the body, must be admitted as at least a concurrent agency ; and when it is borne 

 in mind that the atmosphere in which a number of persons have been confined 

 for some time, becomes actually offensive to the smell in consequence of the 



art. " Asphyxia," by the Author ; the Experimental Essay by Dr. J. Reid, "On the Order 

 of Succession in which the Vital Actions are arrested in Asphyxia," in the "Edinb. Med. 

 and Surg. Journ.," 1841, and in his " Anat., Physiol., and Pathol. Researches;" and the 

 Experimental Inquiry by Mr. Erichsen, in the "Edinb. Med. and Surg. Journ.," 1845. 



