14 Prof. Daniell on Sulphuretted Hydrogen 



who have been exposed to the deleterious influence in small 

 quantities. 



The symptoms, in cases where this gas is breathed in a 

 state of concentration, well known to medical men, are sud- 

 den weakness, and all the signs of asphyxia : the individual 

 becomes suddenly weak and insensible; falls down, and almost 

 immediately expires. When the exposure has been too 

 slight to cause serious mischief, the individual is affected with 

 sickness, colic, imperfectly defined pains in the chest, and 

 lethargy. 



Now, can it be deemed at all improbable, that an agent 

 which is capable of acting with this severity as a direct poison, 

 when mixed in no very high proportion with the atmosphere, 

 should in still less quantities greatly aggravate symptoms of 

 morbific action, which may possibly have their origin in other 

 causes? 



In the very expedition, from the account of which I have 

 already quoted an extract, a circumstance occurred which is 

 almost an experimental confirmation of these views. The 

 first sickness and death in that expedition began at Cape 

 Coast Castle ; three died before entering the river, and the 

 great mortality took place before they reached Damuggoo at 

 the extreme upper end of the Delta, where they only arrived 

 after a voyage of thirty-six days, from the 11th of October to 

 the Kith of November, or twenty-seven from their entrance 

 of the river Nun. 



Now it is worthy of remark, that just before entering the 

 river, in "breaking out" the hold to lighten the vessel, it was 

 discovered that the cause of a " disagreeable vapour, from 

 which they had long suffered, was, that the bags containing 

 the cocoa had rotted, and the cocoa had fallen into the salt 

 bilge-water and there become putrid." Here, then, were the 

 very ingredients for generating sulphuretted hydrogen to a 

 great extent; the lamentable consequence has been before 

 alluded to, namely, three deaths before reaching the river. 

 There can indeed be no doubt that the disagreeable effluvium 

 of bilge-water, which has been carelessly left undisturbed for 

 a long time, is owing to similar decomposition. 



It is doubtless the same circumstance which renders Man- 

 grove swamp so notoriously pestilential in all parts of the 

 torrid zone. The tree only thrives in salt water, and its de- 

 cayed foliage is admirably adapted to act upon the sulphates; 

 and it accounts for the observation, that malarious fevers di- 

 minish as we recede from the coast, although swamp and rank 

 vegetation may still prevail. 



The close investigation which I have since given to the 



