798 ABLIE V. BOCK 



2. Gum Acacia or Gum-Saline Solutions. The use of gum acacia for 

 infusion purposes is a development of the demand during the war for a 

 fluid substitute for blood in the treatment of hemorrhage and shock. Ac- 

 cording to Bayliss (c), gum acacia is a polymerized anhydrid of arabinose. 

 Erlanger and Gasser state that substances similar to gum acacia are widely 

 distributed in the plant kingdom, and are important factors in the nutri- 

 tion of herbivorous animals. When ingested by man these substances are 

 readily utilized in processes of metabolism. Erlanger and Gasser 

 state that about one-half of the amount of gum acacia injected intra- 

 venously is utilized by the organism in the course of twelve hours, but that 

 some of it remains in the body for over forty-eight. Bayliss obtained the 

 pentose test in the blood twenty-four hours after injection of gum-saline. 



Gum acacia may be obtained either in the powder form or in lumps 

 (tears). The lump form is usually purer than the powder. For the 

 purpose of infusion, Bayliss found that a solution of gum between 6 per 

 cent and 7 per cent in strength, in a 0.9 per cent solution of sodium 

 chlorid, has the same viscosity as whole blood, and the same osmotic 

 pressure as the colloids of the plasma. ' Such a solution therefore possesses 

 properties requisite for use in conditions in which an increase in blood 

 volume and sustained elevation of blood pressure are desirable, because 

 it remains in the circulation long enough for the circulatory mechanism 

 to readjust itself. The results obtained by the extensive Use of gum-saline 

 by Drummond and Taylor(d), and others, justify the theoretical and ex- 

 perimental considerations put forward by Bayliss (c). Certain dangers in 

 connection with the use of this solution will be referred to under the sub- 

 ject of reactions. 



The quantity of gum-saline which Bayliss recommended for injection 

 is 750 c.c. A safe rule to follow for this solution, as with others for 

 intravenous use, is to govern the amount given in relation to the body 

 weight. A dose equal to 1 per cent of the body weight, to be repeated,*' if 

 necessary, will usually meet requirements. If a greater addition to the 

 blood volume is desirable, more than this may be given with safety. Gum- 

 saline may be given to cases in shock without overburdening the heart. 

 Its use should be limited to conditions of low blood pressure as a result 

 of hemorrhage and shock. It is not a substitute for red corpuscles and, 

 therefore, can be of no use in treatment for an exsanguinating hemorrhage, 

 for which transfusion of blood alone is indicated. 



The use of the combination of hypertonic solutions of gum acacia and 

 glucose, as recommended by Erlanger and Gasser, has not yet been ex- 

 tensively used clinically. When slowly injected, the great viscosity of 25 

 per cent gum-saline which they used, apparently does not contra-indicate 

 its use. 



3. Gelatin Solutions. A solution of gelatin, 2.5 per cent, in normal 

 saline, as recommended by Hogan on account of its colloidal properties, 



