THE INTRAVENOUS INJECTION OF FLUIDS 791 



effective measure, many solutions have been used to accomplish this end. 

 In the case of a fluid substitute for blood, the solution, according to Bay- 

 liss(c), should possess the same viscosity as blood, in order to raise the 

 blood pressure to a -normal level, and to .exert the same osmotic pressure 

 is the colloids of the blood plasma, which will prevent the loss of fluid 

 from the circulation. If a solution possesses these properties it will tend 



maintain the blood pressure at a normal level for many hours, because 

 e volume of fluid injected remains in the blood vessels for an indefinite 

 time. In order to insure this result, the solution, furthermore, must be 

 colloidal in nature, since the capillary walls are relatively impervious to 

 colloids. The best solution of this nature yet proposed is one containing 

 gum acacia, to the strength of 6 per cent to 7 per cent in 0.9 per cent saline 

 (gum-saline), as described by Bayliss(c). Rons and Wilson, on the other 

 hand, state that a fluid substitute for blood need not haA^e the same viscosity 

 as whole blood. They removed as much as 75 per cent of 'the hemoglobin of 

 rabbits by bleeding and replaced the volume by rabbit's plasma. No great 

 change was observed in the behavior of these animals. However, the fact 

 remains that no artificial solution of low viscosity used up to the present 

 time has proved to be so'useful for the treatment of hemorrhage and shock 

 as the solution recommended by Bayliss. 



Of other colloidal solutions, gelatin in 2.5 per cent solution as recom- 

 mended by Hogan in 1915 has been found useful. More recently, Erlanger 

 and Gasser have proposed the simultaneous use of hypertonic gum-salt 

 solution and hypertonic glucose solution. They have used an 18 per cent 

 solution of glucose and a 25 per cent solution of gum-saline with good 

 results for the treatment of hemorrhage and shock in dogs, and also in a 

 small series of human beings. The beneficial effects thus obtained are 

 explained in part by these authors as due to the internal transfusion 

 effected by the hypertonic solution of glucose, resulting in a still further 

 expansion of the blood volume. This secondary increase of volume is 

 maintained by the hydration-of the excessive amount of gum acacia present 

 in the circulation. 



The failure of isotonic salt solution to maintain blood pressure after 

 hemorrhage is well known. Physiologists have long ago shown that the 

 introduction of normal saline into the blood stream has only a fleeting effect 

 upon the blood pressure, because this fluid leaves the blood stream for the 

 tissues and urine within a few minutes after it is injected. The reason 

 for this is the low viscosity of the solutipn as compared with blood, 

 together with the fact that the walls of the capillaries are especially 

 permeable to all crystalloids. Modifications of normal saline, such as 

 Ringer's solution, hypertonic. and hvpotonic salt solutions, share the same 

 fate as normal saline. 



It is to be remembered that all artificial fluids are substitutes for 

 Mood, and that in the treatment of hemorrhage, transfusion of blood is 



