The presence of a starch splitting ferment in the blood of mammals has long been known and has been the subject of a great many experimental and clinical studies; yet its significance under normal, as well as under pathologic conditions, has remained somewhat of a mystery. This may be due partly to the lack of uniformity and relative inadequacy of the present methods for the quantitative measurement of the enzyme. In connection with other experiments on the external secretion of the pancreas, we became interested in studying blood amylase, and were impressed, as others have been, with certain practical disadvantages of, as well as theoretical objections to, such methods.
Two general types of method have been employed in the measurement of blood and urinary amylase. One has been based on the disappearance of the original starch solution, as revealed by its failure to give an iodine reaction;1 the other,