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A Method of Estimating the Total Volume of Blood contained 



in the Living Body. 



By J. 0. Wakelin Barratt, M.D., D.Sc. Lond., and Warrington 

 Yorke, M.D. Liverpool. 



(Communicated by Prof. Sherrington, F.R.S. Received May 7, — Read May 20, 



1909.) 



(From the Liverpool School of Tropical Medicine.) 



The determination during life of the total volume of blood contained in the 

 living body is usually effected by Haldane's method.* This consists in first 

 estimating the percentage haemoglobin content of the blood and then 

 determining the total haemoglobin content of the circulating fluid, the latter 

 being effected by administering a known volume of carbon monoxide . and 

 observing the extent to which the haemoglobin of the red cells is in 

 combination with this gas. Copeman and Sherrington! determined the 

 volume of the blood in the living body by injecting a measured volume of 

 0"75-per-cent. solution of sodium chloride (sp. gr. T0046) and observing the 

 resulting fall in specific gravity of the blood. 



Recently, while making an investigation upon haemoglobinaemia, we found 

 it necessary to make estimations of the total amount of blood in the living 

 body. This we carried out by : (1) making a haemocrit estimation of the 

 relative proportions, by volume, of red cells and plasma ; (2) injecting a 

 known quantity of dissolved haemoglobin into the blood stream and 

 determining the degree of the resulting hsemoglobinsemia, from which the 

 amount of plasma present can be calculated. The method employed thus 

 consists of two procedures, namely the estimation : (1) of the percentage (by 

 volume) of plasma contained in the blood (A) ; and (2) of the total volume of 

 plasma contained in the body (B). The total volume of the blood is 



\ x 100. 

 A 



1. To carry out the first procedure - 20 c.c. of a 1-per-cent. solution of 

 potassium oxalate was placed in a glass capsule and about 1 c.c. of the blood 

 of the subject of examination, removed from a vein, added. The volume of 

 the mixture was then carefully measured, a haemocrit determination made, 

 and the percentage of plasma in the undiluted blood calculated therefrom. 



* " The Mass and Oxygen Capacity of the Blood in Man," ' Journ. of Physiol.,' 1899 — 

 1900, vol. 25, p. 331. 



+ " Method for Determining the Quantity of Blood in a Living Animal," ' Journ. of 

 Physiol.,' 1890, vol. 11, p. 8 ; also "The Specific Gravity of the Blood," ibid., 1893, p. 71. 



