XIV. PREVENTIVE MEASURES AGAINST LEAD POISONING--_Continued_ 230 XV. DESCRIPTION OF PROCESSES 242 XVI. DESCRIPTION OF PROCESSES--_Continued_ 265 XVII. DESCRIPTION OF PROCESSES--_Continued_ 288 INDEX 305 LIST OF PLATES FACING PAGE PLATE I. 92 PLATE II. 93 PLATE III. 95 PLATE IV. 276 LEAD POISONING AND LEAD ABSORPTION CHAPTER I HISTORICAL--CHEMISTRY OF LEAD The use of lead for various industrial processes and for painting was well known to the ancients. Pliny[1] speaks of white lead, and a method of corroding lead in earthen pots with vinegar, sunk into a heap of dung, as the means by which white lead was made for paint. Agricola mentions three forms of lead--white lead, a compound which was probably bismuth, and metallic lead itself. The alchemists were acquainted with the metal under the name of “saturn,” the term signifying the ease with which the nobler metals, silver and gold, disappear when added to molten lead. Colic caused by lead was also known in ancient times, and is described by Pliny; many other writers refer to it, and Hippocrates was apparently acquainted with lead colic. Not until Stockhusen[2], however, in 1656, ascribed the colic of lead-miners and smelters to the fumes given off from the molten liquid was the definite co-relation between lead and so-called “metallic colic” properly understood, and the symptoms directly traced to poisoning from the metal and its compounds. Æthius, in the early part of the sixteenth century, gave a description of a type of colic called “bellon,” frequently associated with the drinking of certain wines. Tronchin[3], in 1757, discovered that many of these wines were able to dissolve the glaze of the earthenware vessels in which they were stored, the glaze being compounded with litharge. In our own country, John Hunter[4] describes the frequent incidence of “dry bellyache” in the garrison of Jamaica, caused by the consumption of rum which had become contaminated with lead. Many other writers in ancient and historical books on medicine have written on the causation of colic, palsy, and other symptoms, following the ingestion of salts of lead; and as the compounds of lead, mainly the acetate or sugar of lead, were freely used medicinally, often in large doses, opportunities constantly occurred for observing the symptoms produced in susceptible persons. It is not to the present purpose to examine the historical side of the question of lead poisoning, but those interested will find several valuable references in Meillère’s work “Le Saturnisme”[5].