The reactions of lead compounds with serum and serum-models.

THE reactions of lead compounds with serum are of interest, since they determine largely the fate of lead entering the body. The first fairly direct evidence that lead ions react with the phosphate ions of serum was apparently obtained by Aub and his co-workers [1924], who found that haemolysis in hypotonic salt solutions was lessened by addition of soluble lead salts. Lead salts previously mixed with serum had no such effect. At the concentration present in serum, phosphates were the only substances found to have the same power of inhibiting the action of lead as had serum itself. Scremin [1925] added solid lead iodide, carbonate and sulphate to serum, and found phosphate in the sedimented precipitates. Brooks [1927] ultrafiltered serum and aqueous solutions after adding small quantities of lead acetate or of a suspension containing metallic lead and lead hydroxide. The lead in the mixtures was not filterable, and some of the phosphate had ceased to be filterable. The observed mean ratios of phosphorus atoms removed from solution to lead atoms added are given in Table I.