Studies of Blood Regeneration.*

With the exception of Milroy’sl work, no systematic attempt has been made, as far as the writer has been able to ascertain, to follow chemically the changes in alkaline reserve during the period immediately following hemorrhage. Since the Van. Slyke2 method has been devised, such a study has been greatly facilitated. Not only can more extensive data be obtained by the use of this method, due to its simplicity, but also the results so obtained have greater significance due to the fact that changes can be detected too small to influence the hydrogen ion concentration which Milroy determined. The hemorrhages which Milroyl studied with cats and dogs were large (approximately one-third the total volume of blood). In all cases he found a distinct rise in the hydrogen ion concentration of the plasma, determined by the gas chain method; i.e., a loss of reserve alkali. This change was most apparent in the cases in which the plasma was subjected to high concentrations of coz. Samples of blood drawn at intervals of 15 and 45 minutes after hemorrhage showed these distinct changes in reaction. Milroy concluded that there must have been rapid compensatory passage of the tissue fluids into the circulation, the fluid which -first entered the circulation being extremely poor in reserve alkali. The greatest increase in hydrogen ion concentration was found after t>he 15 minute interval.