163 



Though many of the circumstances which influence this re- 

 action are now known to scientific chemists, yet they have 

 so recently been ascertained, and they have found their way 

 so little into purely medical works, and still less into popular 

 treatises, that a short account of some of them may be a 

 proper introduction to the particular case referred to in the 

 title of this paper. No longer ago than 1803, Dr. Lambe, in 

 his " Researches into the Properties of Spring Waters," states 

 that rain water does not corrode lead, but that most spring 

 waters possess the property of corroding and dissolving lead 

 to such an extent, as to render them unfit for the use of man, 

 and that they derive their solvent power from some of the 

 salts present in such waters. In 1809, Guy ton Morveau, 

 from experiments much more scientific and accurate than 

 Dr. Lambe's, came to an opposite conclusion, — that distilled 

 or pure water acts rapidly on lead, converting it into a 

 hydrated oxide (white lead) ; and that some natural waters, 

 which hardly attack lead at all, are prevented from doing so 

 by the salts which they hold in solution. Morveau is right 

 as to distilled water acting on lead. Dr. Lambe was mis- 

 taken. 



Dr. Christison, by experiments which I presume are ori- 

 ginal, and which are detailed at some length in his Treatise 

 on Poisons, 1832, has established with great minuteness, and 

 for the most part with unquestionable accuracy, the circum- 

 stances, or at least many of them, which influence this curious 

 and important reaction. He states that distilled water, de- 

 prived of its gases by boiling, and excluded from contact 

 with the air, has no action on lead. That if the water con- 

 tains the customary gases, (oxygen, nitrogen, and carbonic 

 acid,) the surface of the lead loses its polish and becomes 

 white ; if the surface of the water be not exposed to the 

 air, the action soon comes to a close ; but if the air is 

 allowed free access, the action goes on to a great extent. 



