866 [Assembly 



which I informed Davy, who acknowledged, in his reply, that 

 this reduction was previously unknown to him. Thus within 

 twenty years were two revolutions made in chemical knowledga 

 and theory, and each by the use of a new tool. The balance es- 

 tablished the views of Lavoiser ; the galvanic battery wrought 

 the discoveries of Davy. These discoveries were the foundation 

 of the electro-chemical theory, and became intimately connected 

 with what is called the atomic theory, or the doctrine of definite, 

 equivalent^and^multiple proportions. The study of the mutual 

 and relative influences and re-actions of atoms or molecules, 

 insensible^in size and acting at insensible distances. 



[From the Edinburgh Review, July, 1851.] 



MODERN CHEMISTRY. 

 "Among familiar examples of slow poisoning is the disease 

 known as the painter's colic. It is produced in lead mines and 

 lead works by inhaling lead dust, and elsewhere, not unfrequent- 

 ly, by drinking-water impregnated with lead. The metal being 

 introduced into the system in a soluble form makes its way every- 

 where among the tissues, and lays the foundation of chronic and 

 frequently returning pains. But diluted sulphuric acid, or sul- 

 phureted waters, like those of Harrowgate, render lead insoluble 

 in water, whether in the body or out of it, and are therefore 

 prescribed as common remedies for the painter's colic. Observa- 

 tion, meanwhile, has shown that these remedies, though they 

 assuage or remove the symptoms of the disease, stili leave the 

 lead which caused it diffused in an inert state through the body, 

 ready, when favorable conditions arise, again to act injuriously 

 on the bodily health. 



It is only the other day that M. Melsens, of Brussels, perfected 

 this subdivision of chemical physiology, and gave us the means 

 both of detecting the lurking presence of the metal in the system, 

 and entirely expelling it as a cause of disease. 



A substance, known in chemistry and pharmacy by the name 

 of iodide of potassium, is capable of decomposing the insoluble 

 compounds of lead, and of bringing the metal into a new condi- 

 tion, in which it readily dissolves in water. If a person be 

 poisoned with lead his system struggles to throw it off; the metal 



