The condition of the blood in the new-born has been studied by numerous investigators since Denis1 published the first observations on the subject in 1831. In many instances there has been insufficient data to warrant the conclusions submitted. Statistical results, to be of any great value, must be based on a reasonably large group of cases preferably with repeated observations, and this factor apparently has been disregarded in most of the work published on the blood of the new-born.
In practically every case the blood has been studied at twenty-four hour intervals, usually for the first week and occasionally through the first month. Sometimes the first day has been divided into two or three parts in order to' follow the changing blood picture of the first twenty-four hours.
A study of the literature on this subject shows that, though very marked changes occur during the first forty-eight hours after