Determination of the Amount of Blood in the Central Nervous System Following Injections of Hypertonic Solutions.

The theory that the volume of blood and the volume of fluid within the cranium are inversely related to each other (Monro-Kellie-Burrows) has never been subjected to the test of the direct determination of the amount of blood in the central nervous system following dehydration after injections of hypertonic solutions. Wolff and Forbes 1 noticed contraction of the pial blood-vessels under such experimental conditions, while contrary to their observation Kubie and Hetler 2 described an increase in the color intensity of the brain cortex in color photographs taken before and after injections of 20-30% sodium chloride solutions.

Based on the observations of Voigt 3 that blood, brain and spinal cord do not retain colloidal silver but are free of silver 4 hours after the injection of collargol, the following method was applied for the determination of the amount of blood in the central nervous system: Collargol (Heyden) was dissolved in distilled water, cornsyrup added as a protective colloid and the solution added to an equal volume of either 1.7% or 30% solution of sodium chloride or 100% solution of anhydrous dextrose. The collargol solutions in 0.85% or 15% sodium chloride or 50% dextrose respectively were injected intravenously into dogs under ether anesthesia, 8 cc. per kg. weight. Five to 10 minutes following the injection approximately 30 cc. of blood was taken from the femoral artery and shaken with a few milligrams of heparin to prevent clotting. Immediately thereafter the dogs were killed by puncture of the medulla oblongata. Both jugular veins, carotid arteries and the medulla oblongata en masse were ligated and brain and spinal cord removed. After drying at 120° for the determination of water, blood, brain and spinal cord were ashed with the Neumann method and the silver was determined volumetrically with the Vollhard method, m/50 solutions being used.