PART II 



THE BLOOD AND THE LYMPH 



CHAPTER X 



BLOOD: ITS GENERAL PROPERTIES 

 r.v R. G. Peabce, B.A., M.D. 



The blood, being the carrier of the nutritive and wi ibstai 



the body's metabolism, must at one time <»r another contain all t ; 

 terials which compose the ti^ms in addition to those which an iliar 



to the blood itself. It is a very complex fluid, ami all <>; institw 



are nut fully known. Structurally it is composed of water in which are 

 dissolved various gases ami organic ami inorganic bodies, the c 

 and platelets. 



THE QUANTITY OF BLOOD IN THE BODY 



The nmst accurate method <>t' determining the volume of M 1 in 



the body is bj bleeding and subsequently washing <>ut the bl from 

 the vessels and then estimating the amounl of hemoglobin in the tol 

 fluid (Welcher's method . This method employed in the 

 criminals who had been decapitated gave the weighl of the bl< 

 7.7 and 7.2 per cent of the body weight. Bloodless methods for del 

 mining the total volume of blood are based upon the principle of add 



ing a definite quantity of a known substai to the circulation ai 



estimating its concentration in a sample of blood withdrawn from 



bodj Bhortly afterward. It' the Bubstance can not lea 



ami dues not cause tliiid tn be withdrawn from the tis the total quantity 



of blood in the body can be calculated from 



injected Bubstance in the blood. The must accurate method* 



this principle are Haldane and Smith's, in which carbon n 



is inhaled in a given amount ami the carbon mon 



Bequentlj determined colorimetrically ; and Keitl 



aghty's, which employs vital re. I. a dye of lo 



remains long enough in the bod) )■■ be ihn 



blood, and its entration in the pla • 



