Thirty-five digestions were performed. When 1 gramme of white lead was used--that is, 0·01 per cent., containing 0·75 per cent. of lead oxide--the quantity of lead found as lead oxide in the acid digest varied from 2 to 3 per cent., whilst the amount found in the pancreatic digest varied from 4 to 6·5 per cent. of the added salt. On increasing the amount to 12 grammes--that is, 1 per cent.--the quantity returned in the digest only increased from 1·5 to 2 per cent. In other words, in the addition of larger quantities of material the ratio of solubility did not rise in proportion to the quantity added. Where a direct pancreatic digestion was performed without the preliminary digest of the gastric contents, the amount of lead present in the digest was only about 0·2 per cent. of the quantity added; indeed, it was very much smaller than the amount dissolved out after preliminary acid digestion--that is, if the normal sequence of digestion is followed, the solubility progresses after the gastric digest has been neutralized and pancreatic ferment has been added, whereas very slow action indeed occurs as the result of action of the pancreatic digest alone. Some experiments described by Thomason[12], although carried out without special regard to the physiological question of the progressive nature of digestion, distinctly confirm the point raised. Thus, in a digest of gastric juice, milk, and bread, 5·0 per cent. of lead was dissolved, whereas when pancreatic juice alone was used only 0·4 per cent. was found to be dissolved, a remarkable confirmation of the point under discussion.