The constituents of the blood of infants show significant alterations during the early months of life. Most pronounced, perhaps, is the drop in hemoglobin and red blood cells. Another hitherto unrecognized feature, apparently characteristic of this period, is the rapidity with which the blood decolorizes methylene blue.
This study developed from the observation that the blood of some persons possessed the faculty of decolorizing a weak solution of methylene blue dissolved in sodium citrate, whereas the blood of other persons, under the same well defined experimental conditions, lacked this feature. Further investigation revealed that age played a dominant rôle in this phenomenon, and that a number of intrinsic and extraneous variables influenced the rapidity and intensity of the reaction.
The method employed in this investigation was as follows: A stock solution was prepared by dissolving 200 mg. of methylene blue, U. S. P. medicinal, in 40 cc. of 3