892 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



vided with two small windows ; and it is remarkable that of the 

 twentj-three who were found alive in the morning, many were sub- 

 sequently 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, how- 

 ever, which rivaled it in magnitude. On the night of the first 

 of December, 1848, the deck passengers on board the Irish steamer 

 Londonderry 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 seventy were suiFocated 

 before the morning. 



" It cannot be too strongly impressed upon the medical practitioner, 

 however, and through him upon the public in general, that the con- 

 tinued respiration 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 fermentible 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 even the presence of 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, it fol- 

 lows that these oxydating processes which minister to the elimination 

 of efiete matter from the system, must be imperfectly performed, and 

 that an accumulation of substances tending to putrescence must take 

 place in the blood. Ilence there will probably be a considerable 

 increase in the amount of such matters in the pulmonary and cuta- 

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

 with carbonic acid, but also with organic matter in a state of decompo- 

 sition, and will thus favor the accumulation of both these morbific sub- 

 stances in the blood, instead of efl'ecting that constant and complete 

 removal of them, which is otie of the chief ends of the respiratory process 

 to accomplish. It lias been customary to consider the consequences of 

 imperfect respiration, as being exerted merely in promoting 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 



